diff --git a/homeassistant/components/openai_conversation/__init__.py b/homeassistant/components/openai_conversation/__init__.py
index 71effe83884..a5b13ded375 100644
--- a/homeassistant/components/openai_conversation/__init__.py
+++ b/homeassistant/components/openai_conversation/__init__.py
@@ -19,7 +19,7 @@ from openai.types.responses import (
 )
 import voluptuous as vol
 
-from homeassistant.config_entries import ConfigEntry
+from homeassistant.config_entries import ConfigEntry, ConfigSubentry
 from homeassistant.const import CONF_API_KEY, Platform
 from homeassistant.core import (
     HomeAssistant,
@@ -32,7 +32,12 @@ from homeassistant.exceptions import (
     HomeAssistantError,
     ServiceValidationError,
 )
-from homeassistant.helpers import config_validation as cv, selector
+from homeassistant.helpers import (
+    config_validation as cv,
+    device_registry as dr,
+    entity_registry as er,
+    selector,
+)
 from homeassistant.helpers.httpx_client import get_async_client
 from homeassistant.helpers.typing import ConfigType
 
@@ -73,6 +78,7 @@ def encode_file(file_path: str) -> tuple[str, str]:
 
 async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
     """Set up OpenAI Conversation."""
+    await async_migrate_integration(hass)
 
     async def render_image(call: ServiceCall) -> ServiceResponse:
         """Render an image with dall-e."""
@@ -118,7 +124,21 @@ async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
                 translation_placeholders={"config_entry": entry_id},
             )
 
-        model: str = entry.options.get(CONF_CHAT_MODEL, RECOMMENDED_CHAT_MODEL)
+        # Get first conversation subentry for options
+        conversation_subentry = next(
+            (
+                sub
+                for sub in entry.subentries.values()
+                if sub.subentry_type == "conversation"
+            ),
+            None,
+        )
+        if not conversation_subentry:
+            raise ServiceValidationError("No conversation configuration found")
+
+        model: str = conversation_subentry.data.get(
+            CONF_CHAT_MODEL, RECOMMENDED_CHAT_MODEL
+        )
         client: openai.AsyncClient = entry.runtime_data
 
         content: ResponseInputMessageContentListParam = [
@@ -169,11 +189,11 @@ async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
             model_args = {
                 "model": model,
                 "input": messages,
-                "max_output_tokens": entry.options.get(
+                "max_output_tokens": conversation_subentry.data.get(
                     CONF_MAX_TOKENS, RECOMMENDED_MAX_TOKENS
                 ),
-                "top_p": entry.options.get(CONF_TOP_P, RECOMMENDED_TOP_P),
-                "temperature": entry.options.get(
+                "top_p": conversation_subentry.data.get(CONF_TOP_P, RECOMMENDED_TOP_P),
+                "temperature": conversation_subentry.data.get(
                     CONF_TEMPERATURE, RECOMMENDED_TEMPERATURE
                 ),
                 "user": call.context.user_id,
@@ -182,7 +202,7 @@ async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
 
             if model.startswith("o"):
                 model_args["reasoning"] = {
-                    "effort": entry.options.get(
+                    "effort": conversation_subentry.data.get(
                         CONF_REASONING_EFFORT, RECOMMENDED_REASONING_EFFORT
                     )
                 }
@@ -269,3 +289,68 @@ async def async_setup_entry(hass: HomeAssistant, entry: OpenAIConfigEntry) -> bo
 async def async_unload_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     """Unload OpenAI."""
     return await hass.config_entries.async_unload_platforms(entry, PLATFORMS)
+
+
+async def async_migrate_integration(hass: HomeAssistant) -> None:
+    """Migrate integration entry structure."""
+
+    entries = hass.config_entries.async_entries(DOMAIN)
+    if not any(entry.version == 1 for entry in entries):
+        return
+
+    api_keys_entries: dict[str, ConfigEntry] = {}
+    entity_registry = er.async_get(hass)
+    device_registry = dr.async_get(hass)
+
+    for entry in entries:
+        use_existing = False
+        subentry = ConfigSubentry(
+            data=entry.options,
+            subentry_type="conversation",
+            title=entry.title,
+            unique_id=None,
+        )
+        if entry.data[CONF_API_KEY] not in api_keys_entries:
+            use_existing = True
+            api_keys_entries[entry.data[CONF_API_KEY]] = entry
+
+        parent_entry = api_keys_entries[entry.data[CONF_API_KEY]]
+
+        hass.config_entries.async_add_subentry(parent_entry, subentry)
+        conversation_entity = entity_registry.async_get_entity_id(
+            "conversation",
+            DOMAIN,
+            entry.entry_id,
+        )
+        if conversation_entity is not None:
+            entity_registry.async_update_entity(
+                conversation_entity,
+                config_entry_id=parent_entry.entry_id,
+                config_subentry_id=subentry.subentry_id,
+                new_unique_id=subentry.subentry_id,
+            )
+
+        device = device_registry.async_get_device(
+            identifiers={(DOMAIN, entry.entry_id)}
+        )
+        if device is not None:
+            device_registry.async_update_device(
+                device.id,
+                new_identifiers={(DOMAIN, subentry.subentry_id)},
+                add_config_subentry_id=subentry.subentry_id,
+                add_config_entry_id=parent_entry.entry_id,
+            )
+            if parent_entry.entry_id != entry.entry_id:
+                device_registry.async_update_device(
+                    device.id,
+                    remove_config_entry_id=entry.entry_id,
+                )
+
+        if not use_existing:
+            await hass.config_entries.async_remove(entry.entry_id)
+        else:
+            hass.config_entries.async_update_entry(
+                entry,
+                options={},
+                version=2,
+            )
diff --git a/homeassistant/components/openai_conversation/config_flow.py b/homeassistant/components/openai_conversation/config_flow.py
index 60d81bf6745..a9a444cf3dd 100644
--- a/homeassistant/components/openai_conversation/config_flow.py
+++ b/homeassistant/components/openai_conversation/config_flow.py
@@ -13,17 +13,20 @@ from voluptuous_openapi import convert
 from homeassistant.components.zone import ENTITY_ID_HOME
 from homeassistant.config_entries import (
     ConfigEntry,
+    ConfigEntryState,
     ConfigFlow,
     ConfigFlowResult,
-    OptionsFlow,
+    ConfigSubentryFlow,
+    SubentryFlowResult,
 )
 from homeassistant.const import (
     ATTR_LATITUDE,
     ATTR_LONGITUDE,
     CONF_API_KEY,
     CONF_LLM_HASS_API,
+    CONF_NAME,
 )
-from homeassistant.core import HomeAssistant
+from homeassistant.core import HomeAssistant, callback
 from homeassistant.helpers import llm
 from homeassistant.helpers.httpx_client import get_async_client
 from homeassistant.helpers.selector import (
@@ -52,6 +55,7 @@ from .const import (
     CONF_WEB_SEARCH_REGION,
     CONF_WEB_SEARCH_TIMEZONE,
     CONF_WEB_SEARCH_USER_LOCATION,
+    DEFAULT_CONVERSATION_NAME,
     DOMAIN,
     RECOMMENDED_CHAT_MODEL,
     RECOMMENDED_MAX_TOKENS,
@@ -94,7 +98,7 @@ async def validate_input(hass: HomeAssistant, data: dict[str, Any]) -> None:
 class OpenAIConfigFlow(ConfigFlow, domain=DOMAIN):
     """Handle a config flow for OpenAI Conversation."""
 
-    VERSION = 1
+    VERSION = 2
 
     async def async_step_user(
         self, user_input: dict[str, Any] | None = None
@@ -107,6 +111,7 @@ class OpenAIConfigFlow(ConfigFlow, domain=DOMAIN):
 
         errors: dict[str, str] = {}
 
+        self._async_abort_entries_match(user_input)
         try:
             await validate_input(self.hass, user_input)
         except openai.APIConnectionError:
@@ -120,32 +125,61 @@ class OpenAIConfigFlow(ConfigFlow, domain=DOMAIN):
             return self.async_create_entry(
                 title="ChatGPT",
                 data=user_input,
-                options=RECOMMENDED_OPTIONS,
+                subentries=[
+                    {
+                        "subentry_type": "conversation",
+                        "data": RECOMMENDED_OPTIONS,
+                        "title": DEFAULT_CONVERSATION_NAME,
+                        "unique_id": None,
+                    }
+                ],
             )
 
         return self.async_show_form(
             step_id="user", data_schema=STEP_USER_DATA_SCHEMA, errors=errors
         )
 
-    @staticmethod
-    def async_get_options_flow(
-        config_entry: ConfigEntry,
-    ) -> OptionsFlow:
-        """Create the options flow."""
-        return OpenAIOptionsFlow(config_entry)
+    @classmethod
+    @callback
+    def async_get_supported_subentry_types(
+        cls, config_entry: ConfigEntry
+    ) -> dict[str, type[ConfigSubentryFlow]]:
+        """Return subentries supported by this integration."""
+        return {"conversation": ConversationSubentryFlowHandler}
 
 
-class OpenAIOptionsFlow(OptionsFlow):
-    """OpenAI config flow options handler."""
+class ConversationSubentryFlowHandler(ConfigSubentryFlow):
+    """Flow for managing conversation subentries."""
 
-    def __init__(self, config_entry: ConfigEntry) -> None:
-        """Initialize options flow."""
-        self.options = config_entry.options.copy()
+    last_rendered_recommended = False
+    options: dict[str, Any]
+
+    @property
+    def _is_new(self) -> bool:
+        """Return if this is a new subentry."""
+        return self.source == "user"
+
+    async def async_step_user(
+        self, user_input: dict[str, Any] | None = None
+    ) -> SubentryFlowResult:
+        """Add a subentry."""
+        self.options = RECOMMENDED_OPTIONS.copy()
+        return await self.async_step_init()
+
+    async def async_step_reconfigure(
+        self, user_input: dict[str, Any] | None = None
+    ) -> SubentryFlowResult:
+        """Handle reconfiguration of a subentry."""
+        self.options = self._get_reconfigure_subentry().data.copy()
+        return await self.async_step_init()
 
     async def async_step_init(
         self, user_input: dict[str, Any] | None = None
-    ) -> ConfigFlowResult:
+    ) -> SubentryFlowResult:
         """Manage initial options."""
+        # abort if entry is not loaded
+        if self._get_entry().state != ConfigEntryState.LOADED:
+            return self.async_abort(reason="entry_not_loaded")
         options = self.options
 
         hass_apis: list[SelectOptionDict] = [
@@ -160,25 +194,47 @@ class OpenAIOptionsFlow(OptionsFlow):
         ):
             options[CONF_LLM_HASS_API] = [suggested_llm_apis]
 
-        step_schema: VolDictType = {
-            vol.Optional(
-                CONF_PROMPT,
-                description={"suggested_value": llm.DEFAULT_INSTRUCTIONS_PROMPT},
-            ): TemplateSelector(),
-            vol.Optional(CONF_LLM_HASS_API): SelectSelector(
-                SelectSelectorConfig(options=hass_apis, multiple=True)
-            ),
-            vol.Required(
-                CONF_RECOMMENDED, default=options.get(CONF_RECOMMENDED, False)
-            ): bool,
-        }
+        step_schema: VolDictType = {}
+
+        if self._is_new:
+            step_schema[vol.Required(CONF_NAME, default=DEFAULT_CONVERSATION_NAME)] = (
+                str
+            )
+
+        step_schema.update(
+            {
+                vol.Optional(
+                    CONF_PROMPT,
+                    description={
+                        "suggested_value": options.get(
+                            CONF_PROMPT, llm.DEFAULT_INSTRUCTIONS_PROMPT
+                        )
+                    },
+                ): TemplateSelector(),
+                vol.Optional(CONF_LLM_HASS_API): SelectSelector(
+                    SelectSelectorConfig(options=hass_apis, multiple=True)
+                ),
+                vol.Required(
+                    CONF_RECOMMENDED, default=options.get(CONF_RECOMMENDED, False)
+                ): bool,
+            }
+        )
 
         if user_input is not None:
             if not user_input.get(CONF_LLM_HASS_API):
                 user_input.pop(CONF_LLM_HASS_API, None)
 
             if user_input[CONF_RECOMMENDED]:
-                return self.async_create_entry(title="", data=user_input)
+                if self._is_new:
+                    return self.async_create_entry(
+                        title=user_input.pop(CONF_NAME),
+                        data=user_input,
+                    )
+                return self.async_update_and_abort(
+                    self._get_entry(),
+                    self._get_reconfigure_subentry(),
+                    data=user_input,
+                )
 
             options.update(user_input)
             if CONF_LLM_HASS_API in options and CONF_LLM_HASS_API not in user_input:
@@ -194,7 +250,7 @@ class OpenAIOptionsFlow(OptionsFlow):
 
     async def async_step_advanced(
         self, user_input: dict[str, Any] | None = None
-    ) -> ConfigFlowResult:
+    ) -> SubentryFlowResult:
         """Manage advanced options."""
         options = self.options
         errors: dict[str, str] = {}
@@ -236,7 +292,7 @@ class OpenAIOptionsFlow(OptionsFlow):
 
     async def async_step_model(
         self, user_input: dict[str, Any] | None = None
-    ) -> ConfigFlowResult:
+    ) -> SubentryFlowResult:
         """Manage model-specific options."""
         options = self.options
         errors: dict[str, str] = {}
@@ -303,7 +359,16 @@ class OpenAIOptionsFlow(OptionsFlow):
             }
 
         if not step_schema:
-            return self.async_create_entry(title="", data=options)
+            if self._is_new:
+                return self.async_create_entry(
+                    title=options.pop(CONF_NAME, DEFAULT_CONVERSATION_NAME),
+                    data=options,
+                )
+            return self.async_update_and_abort(
+                self._get_entry(),
+                self._get_reconfigure_subentry(),
+                data=options,
+            )
 
         if user_input is not None:
             if user_input.get(CONF_WEB_SEARCH):
@@ -316,7 +381,16 @@ class OpenAIOptionsFlow(OptionsFlow):
                     options.pop(CONF_WEB_SEARCH_TIMEZONE, None)
 
             options.update(user_input)
-            return self.async_create_entry(title="", data=options)
+            if self._is_new:
+                return self.async_create_entry(
+                    title=options.pop(CONF_NAME, DEFAULT_CONVERSATION_NAME),
+                    data=options,
+                )
+            return self.async_update_and_abort(
+                self._get_entry(),
+                self._get_reconfigure_subentry(),
+                data=options,
+            )
 
         return self.async_show_form(
             step_id="model",
@@ -332,7 +406,7 @@ class OpenAIOptionsFlow(OptionsFlow):
         zone_home = self.hass.states.get(ENTITY_ID_HOME)
         if zone_home is not None:
             client = openai.AsyncOpenAI(
-                api_key=self.config_entry.data[CONF_API_KEY],
+                api_key=self._get_entry().data[CONF_API_KEY],
                 http_client=get_async_client(self.hass),
             )
             location_schema = vol.Schema(
diff --git a/homeassistant/components/openai_conversation/const.py b/homeassistant/components/openai_conversation/const.py
index f022b4840eb..f90c05eed79 100644
--- a/homeassistant/components/openai_conversation/const.py
+++ b/homeassistant/components/openai_conversation/const.py
@@ -5,6 +5,8 @@ import logging
 DOMAIN = "openai_conversation"
 LOGGER: logging.Logger = logging.getLogger(__package__)
 
+DEFAULT_CONVERSATION_NAME = "OpenAI Conversation"
+
 CONF_CHAT_MODEL = "chat_model"
 CONF_FILENAMES = "filenames"
 CONF_MAX_TOKENS = "max_tokens"
diff --git a/homeassistant/components/openai_conversation/conversation.py b/homeassistant/components/openai_conversation/conversation.py
index 8fea4613ce0..e63bbf32c35 100644
--- a/homeassistant/components/openai_conversation/conversation.py
+++ b/homeassistant/components/openai_conversation/conversation.py
@@ -34,7 +34,7 @@ from openai.types.responses.web_search_tool_param import UserLocation
 from voluptuous_openapi import convert
 
 from homeassistant.components import assist_pipeline, conversation
-from homeassistant.config_entries import ConfigEntry
+from homeassistant.config_entries import ConfigEntry, ConfigSubentry
 from homeassistant.const import CONF_LLM_HASS_API, MATCH_ALL
 from homeassistant.core import HomeAssistant
 from homeassistant.exceptions import HomeAssistantError
@@ -76,8 +76,14 @@ async def async_setup_entry(
     async_add_entities: AddConfigEntryEntitiesCallback,
 ) -> None:
     """Set up conversation entities."""
-    agent = OpenAIConversationEntity(config_entry)
-    async_add_entities([agent])
+    for subentry in config_entry.subentries.values():
+        if subentry.subentry_type != "conversation":
+            continue
+
+        async_add_entities(
+            [OpenAIConversationEntity(config_entry, subentry)],
+            config_subentry_id=subentry.subentry_id,
+        )
 
 
 def _format_tool(
@@ -229,22 +235,22 @@ class OpenAIConversationEntity(
 ):
     """OpenAI conversation agent."""
 
-    _attr_has_entity_name = True
-    _attr_name = None
     _attr_supports_streaming = True
 
-    def __init__(self, entry: OpenAIConfigEntry) -> None:
+    def __init__(self, entry: OpenAIConfigEntry, subentry: ConfigSubentry) -> None:
         """Initialize the agent."""
         self.entry = entry
-        self._attr_unique_id = entry.entry_id
+        self.subentry = subentry
+        self._attr_name = subentry.title
+        self._attr_unique_id = subentry.subentry_id
         self._attr_device_info = dr.DeviceInfo(
-            identifiers={(DOMAIN, entry.entry_id)},
-            name=entry.title,
+            identifiers={(DOMAIN, subentry.subentry_id)},
+            name=subentry.title,
             manufacturer="OpenAI",
-            model="ChatGPT",
+            model=entry.data.get(CONF_CHAT_MODEL, RECOMMENDED_CHAT_MODEL),
             entry_type=dr.DeviceEntryType.SERVICE,
         )
-        if self.entry.options.get(CONF_LLM_HASS_API):
+        if self.subentry.data.get(CONF_LLM_HASS_API):
             self._attr_supported_features = (
                 conversation.ConversationEntityFeature.CONTROL
             )
@@ -276,7 +282,7 @@ class OpenAIConversationEntity(
         chat_log: conversation.ChatLog,
     ) -> conversation.ConversationResult:
         """Process the user input and call the API."""
-        options = self.entry.options
+        options = self.subentry.data
 
         try:
             await chat_log.async_provide_llm_data(
@@ -304,7 +310,7 @@ class OpenAIConversationEntity(
         chat_log: conversation.ChatLog,
     ) -> None:
         """Generate an answer for the chat log."""
-        options = self.entry.options
+        options = self.subentry.data
 
         tools: list[ToolParam] | None = None
         if chat_log.llm_api:
diff --git a/homeassistant/components/openai_conversation/strings.json b/homeassistant/components/openai_conversation/strings.json
index 351e82ec11f..ffbe84337b7 100644
--- a/homeassistant/components/openai_conversation/strings.json
+++ b/homeassistant/components/openai_conversation/strings.json
@@ -11,47 +11,63 @@
       "cannot_connect": "[%key:common::config_flow::error::cannot_connect%]",
       "invalid_auth": "[%key:common::config_flow::error::invalid_auth%]",
       "unknown": "[%key:common::config_flow::error::unknown%]"
+    },
+    "abort": {
+      "already_configured": "[%key:common::config_flow::abort::already_configured_service%]"
     }
   },
-  "options": {
-    "step": {
-      "init": {
-        "data": {
-          "prompt": "Instructions",
-          "llm_hass_api": "[%key:common::config_flow::data::llm_hass_api%]",
-          "recommended": "Recommended model settings"
+  "config_subentries": {
+    "conversation": {
+      "initiate_flow": {
+        "user": "Add conversation agent",
+        "reconfigure": "Reconfigure conversation agent"
+      },
+      "entry_type": "Conversation agent",
+
+      "step": {
+        "init": {
+          "data": {
+            "name": "[%key:common::config_flow::data::name%]",
+            "prompt": "Instructions",
+            "llm_hass_api": "[%key:common::config_flow::data::llm_hass_api%]",
+            "recommended": "Recommended model settings"
+          },
+          "data_description": {
+            "prompt": "Instruct how the LLM should respond. This can be a template."
+          }
         },
-        "data_description": {
-          "prompt": "Instruct how the LLM should respond. This can be a template."
+        "advanced": {
+          "title": "Advanced settings",
+          "data": {
+            "chat_model": "[%key:common::generic::model%]",
+            "max_tokens": "Maximum tokens to return in response",
+            "temperature": "Temperature",
+            "top_p": "Top P"
+          }
+        },
+        "model": {
+          "title": "Model-specific options",
+          "data": {
+            "reasoning_effort": "Reasoning effort",
+            "web_search": "Enable web search",
+            "search_context_size": "Search context size",
+            "user_location": "Include home location"
+          },
+          "data_description": {
+            "reasoning_effort": "How many reasoning tokens the model should generate before creating a response to the prompt",
+            "web_search": "Allow the model to search the web for the latest information before generating a response",
+            "search_context_size": "High level guidance for the amount of context window space to use for the search",
+            "user_location": "Refine search results based on geography"
+          }
         }
       },
-      "advanced": {
-        "title": "Advanced settings",
-        "data": {
-          "chat_model": "[%key:common::generic::model%]",
-          "max_tokens": "Maximum tokens to return in response",
-          "temperature": "Temperature",
-          "top_p": "Top P"
-        }
+      "abort": {
+        "reconfigure_successful": "[%key:common::config_flow::abort::reconfigure_successful%]",
+        "entry_not_loaded": "Cannot add things while the configuration is disabled."
       },
-      "model": {
-        "title": "Model-specific options",
-        "data": {
-          "reasoning_effort": "Reasoning effort",
-          "web_search": "Enable web search",
-          "search_context_size": "Search context size",
-          "user_location": "Include home location"
-        },
-        "data_description": {
-          "reasoning_effort": "How many reasoning tokens the model should generate before creating a response to the prompt",
-          "web_search": "Allow the model to search the web for the latest information before generating a response",
-          "search_context_size": "High level guidance for the amount of context window space to use for the search",
-          "user_location": "Refine search results based on geography"
-        }
+      "error": {
+        "model_not_supported": "This model is not supported, please select a different model"
       }
-    },
-    "error": {
-      "model_not_supported": "This model is not supported, please select a different model"
     }
   },
   "selector": {
diff --git a/tests/components/openai_conversation/conftest.py b/tests/components/openai_conversation/conftest.py
index 4639d0dc8e0..aa17c333a79 100644
--- a/tests/components/openai_conversation/conftest.py
+++ b/tests/components/openai_conversation/conftest.py
@@ -4,6 +4,7 @@ from unittest.mock import patch
 
 import pytest
 
+from homeassistant.components.openai_conversation.const import DEFAULT_CONVERSATION_NAME
 from homeassistant.const import CONF_LLM_HASS_API
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers import llm
@@ -21,6 +22,15 @@ def mock_config_entry(hass: HomeAssistant) -> MockConfigEntry:
         data={
             "api_key": "bla",
         },
+        version=2,
+        subentries_data=[
+            {
+                "data": {},
+                "subentry_type": "conversation",
+                "title": DEFAULT_CONVERSATION_NAME,
+                "unique_id": None,
+            }
+        ],
     )
     entry.add_to_hass(hass)
     return entry
@@ -31,8 +41,10 @@ def mock_config_entry_with_assist(
     hass: HomeAssistant, mock_config_entry: MockConfigEntry
 ) -> MockConfigEntry:
     """Mock a config entry with assist."""
-    hass.config_entries.async_update_entry(
-        mock_config_entry, options={CONF_LLM_HASS_API: llm.LLM_API_ASSIST}
+    hass.config_entries.async_update_subentry(
+        mock_config_entry,
+        next(iter(mock_config_entry.subentries.values())),
+        data={CONF_LLM_HASS_API: llm.LLM_API_ASSIST},
     )
     return mock_config_entry
 
diff --git a/tests/components/openai_conversation/snapshots/test_conversation.ambr b/tests/components/openai_conversation/snapshots/test_conversation.ambr
index 0f874969aff..48ad0878b2f 100644
--- a/tests/components/openai_conversation/snapshots/test_conversation.ambr
+++ b/tests/components/openai_conversation/snapshots/test_conversation.ambr
@@ -6,7 +6,7 @@
       'role': 'user',
     }),
     dict({
-      'agent_id': 'conversation.openai',
+      'agent_id': 'conversation.openai_conversation',
       'content': None,
       'role': 'assistant',
       'tool_calls': list([
@@ -20,14 +20,14 @@
       ]),
     }),
     dict({
-      'agent_id': 'conversation.openai',
+      'agent_id': 'conversation.openai_conversation',
       'role': 'tool_result',
       'tool_call_id': 'call_call_1',
       'tool_name': 'test_tool',
       'tool_result': 'value1',
     }),
     dict({
-      'agent_id': 'conversation.openai',
+      'agent_id': 'conversation.openai_conversation',
       'content': None,
       'role': 'assistant',
       'tool_calls': list([
@@ -41,14 +41,14 @@
       ]),
     }),
     dict({
-      'agent_id': 'conversation.openai',
+      'agent_id': 'conversation.openai_conversation',
       'role': 'tool_result',
       'tool_call_id': 'call_call_2',
       'tool_name': 'test_tool',
       'tool_result': 'value2',
     }),
     dict({
-      'agent_id': 'conversation.openai',
+      'agent_id': 'conversation.openai_conversation',
       'content': 'Cool',
       'role': 'assistant',
       'tool_calls': None,
@@ -62,7 +62,7 @@
       'role': 'user',
     }),
     dict({
-      'agent_id': 'conversation.openai',
+      'agent_id': 'conversation.openai_conversation',
       'content': None,
       'role': 'assistant',
       'tool_calls': list([
@@ -76,14 +76,14 @@
       ]),
     }),
     dict({
-      'agent_id': 'conversation.openai',
+      'agent_id': 'conversation.openai_conversation',
       'role': 'tool_result',
       'tool_call_id': 'call_call_1',
       'tool_name': 'test_tool',
       'tool_result': 'value1',
     }),
     dict({
-      'agent_id': 'conversation.openai',
+      'agent_id': 'conversation.openai_conversation',
       'content': 'Cool',
       'role': 'assistant',
       'tool_calls': None,
diff --git a/tests/components/openai_conversation/test_config_flow.py b/tests/components/openai_conversation/test_config_flow.py
index ad5bbffaed3..b77542fbab3 100644
--- a/tests/components/openai_conversation/test_config_flow.py
+++ b/tests/components/openai_conversation/test_config_flow.py
@@ -24,12 +24,13 @@ from homeassistant.components.openai_conversation.const import (
     CONF_WEB_SEARCH_REGION,
     CONF_WEB_SEARCH_TIMEZONE,
     CONF_WEB_SEARCH_USER_LOCATION,
+    DEFAULT_CONVERSATION_NAME,
     DOMAIN,
     RECOMMENDED_CHAT_MODEL,
     RECOMMENDED_MAX_TOKENS,
     RECOMMENDED_TOP_P,
 )
-from homeassistant.const import CONF_LLM_HASS_API
+from homeassistant.const import CONF_API_KEY, CONF_LLM_HASS_API
 from homeassistant.core import HomeAssistant
 from homeassistant.data_entry_flow import FlowResultType
 
@@ -72,42 +73,132 @@ async def test_form(hass: HomeAssistant) -> None:
     assert result2["data"] == {
         "api_key": "bla",
     }
-    assert result2["options"] == RECOMMENDED_OPTIONS
+    assert result2["options"] == {}
+    assert result2["subentries"] == [
+        {
+            "subentry_type": "conversation",
+            "data": RECOMMENDED_OPTIONS,
+            "title": DEFAULT_CONVERSATION_NAME,
+            "unique_id": None,
+        }
+    ]
     assert len(mock_setup_entry.mock_calls) == 1
 
 
-async def test_options_recommended(
+async def test_duplicate_entry(hass: HomeAssistant) -> None:
+    """Test we abort on duplicate config entry."""
+    MockConfigEntry(
+        domain=DOMAIN,
+        data={CONF_API_KEY: "bla"},
+    ).add_to_hass(hass)
+
+    result = await hass.config_entries.flow.async_init(
+        DOMAIN, context={"source": config_entries.SOURCE_USER}
+    )
+    assert result["type"] is FlowResultType.FORM
+    assert not result["errors"]
+
+    with patch(
+        "homeassistant.components.openai_conversation.config_flow.openai.resources.models.AsyncModels.list",
+    ):
+        result = await hass.config_entries.flow.async_configure(
+            result["flow_id"],
+            {
+                CONF_API_KEY: "bla",
+            },
+        )
+
+    assert result["type"] is FlowResultType.ABORT
+    assert result["reason"] == "already_configured"
+
+
+async def test_creating_conversation_subentry(
+    hass: HomeAssistant,
+    mock_init_component: None,
+    mock_config_entry: MockConfigEntry,
+) -> None:
+    """Test creating a conversation subentry."""
+    mock_config_entry.add_to_hass(hass)
+
+    result = await hass.config_entries.subentries.async_init(
+        (mock_config_entry.entry_id, "conversation"),
+        context={"source": config_entries.SOURCE_USER},
+    )
+
+    assert result["type"] is FlowResultType.FORM
+    assert result["step_id"] == "init"
+    assert not result["errors"]
+
+    result2 = await hass.config_entries.subentries.async_configure(
+        result["flow_id"],
+        {"name": "My Custom Agent", **RECOMMENDED_OPTIONS},
+    )
+    await hass.async_block_till_done()
+
+    assert result2["type"] is FlowResultType.CREATE_ENTRY
+    assert result2["title"] == "My Custom Agent"
+
+    processed_options = RECOMMENDED_OPTIONS.copy()
+    processed_options[CONF_PROMPT] = processed_options[CONF_PROMPT].strip()
+
+    assert result2["data"] == processed_options
+
+
+async def test_creating_conversation_subentry_not_loaded(
+    hass: HomeAssistant,
+    mock_init_component,
+    mock_config_entry: MockConfigEntry,
+) -> None:
+    """Test creating a conversation subentry when entry is not loaded."""
+    await hass.config_entries.async_unload(mock_config_entry.entry_id)
+    with patch(
+        "homeassistant.components.openai_conversation.config_flow.openai.resources.models.AsyncModels.list",
+        return_value=[],
+    ):
+        result = await hass.config_entries.subentries.async_init(
+            (mock_config_entry.entry_id, "conversation"),
+            context={"source": config_entries.SOURCE_USER},
+        )
+
+    assert result["type"] is FlowResultType.ABORT
+    assert result["reason"] == "entry_not_loaded"
+
+
+async def test_subentry_recommended(
     hass: HomeAssistant, mock_config_entry, mock_init_component
 ) -> None:
-    """Test the options flow with recommended settings."""
-    options_flow = await hass.config_entries.options.async_init(
-        mock_config_entry.entry_id
+    """Test the subentry flow with recommended settings."""
+    subentry = next(iter(mock_config_entry.subentries.values()))
+    subentry_flow = await mock_config_entry.start_subentry_reconfigure_flow(
+        hass, subentry.subentry_id
     )
-    options = await hass.config_entries.options.async_configure(
-        options_flow["flow_id"],
+    options = await hass.config_entries.subentries.async_configure(
+        subentry_flow["flow_id"],
         {
             "prompt": "Speak like a pirate",
             "recommended": True,
         },
     )
     await hass.async_block_till_done()
-    assert options["type"] is FlowResultType.CREATE_ENTRY
-    assert options["data"]["prompt"] == "Speak like a pirate"
+    assert options["type"] is FlowResultType.ABORT
+    assert options["reason"] == "reconfigure_successful"
+    assert subentry.data["prompt"] == "Speak like a pirate"
 
 
-async def test_options_unsupported_model(
+async def test_subentry_unsupported_model(
     hass: HomeAssistant, mock_config_entry, mock_init_component
 ) -> None:
-    """Test the options form giving error about models not supported."""
-    options_flow = await hass.config_entries.options.async_init(
-        mock_config_entry.entry_id
+    """Test the subentry form giving error about models not supported."""
+    subentry = next(iter(mock_config_entry.subentries.values()))
+    subentry_flow = await mock_config_entry.start_subentry_reconfigure_flow(
+        hass, subentry.subentry_id
     )
-    assert options_flow["type"] == FlowResultType.FORM
-    assert options_flow["step_id"] == "init"
+    assert subentry_flow["type"] == FlowResultType.FORM
+    assert subentry_flow["step_id"] == "init"
 
     # Configure initial step
-    options_flow = await hass.config_entries.options.async_configure(
-        options_flow["flow_id"],
+    subentry_flow = await hass.config_entries.subentries.async_configure(
+        subentry_flow["flow_id"],
         {
             CONF_RECOMMENDED: False,
             CONF_PROMPT: "Speak like a pirate",
@@ -115,19 +206,19 @@ async def test_options_unsupported_model(
         },
     )
     await hass.async_block_till_done()
-    assert options_flow["type"] == FlowResultType.FORM
-    assert options_flow["step_id"] == "advanced"
+    assert subentry_flow["type"] == FlowResultType.FORM
+    assert subentry_flow["step_id"] == "advanced"
 
     # Configure advanced step
-    options_flow = await hass.config_entries.options.async_configure(
-        options_flow["flow_id"],
+    subentry_flow = await hass.config_entries.subentries.async_configure(
+        subentry_flow["flow_id"],
         {
             CONF_CHAT_MODEL: "o1-mini",
         },
     )
     await hass.async_block_till_done()
-    assert options_flow["type"] is FlowResultType.FORM
-    assert options_flow["errors"] == {"chat_model": "model_not_supported"}
+    assert subentry_flow["type"] is FlowResultType.FORM
+    assert subentry_flow["errors"] == {"chat_model": "model_not_supported"}
 
 
 @pytest.mark.parametrize(
@@ -494,7 +585,7 @@ async def test_form_invalid_auth(hass: HomeAssistant, side_effect, error) -> Non
         ),
     ],
 )
-async def test_options_switching(
+async def test_subentry_switching(
     hass: HomeAssistant,
     mock_config_entry,
     mock_init_component,
@@ -502,16 +593,22 @@ async def test_options_switching(
     new_options,
     expected_options,
 ) -> None:
-    """Test the options form."""
-    hass.config_entries.async_update_entry(mock_config_entry, options=current_options)
-    options = await hass.config_entries.options.async_init(mock_config_entry.entry_id)
-    assert options["step_id"] == "init"
+    """Test the subentry form."""
+    subentry = next(iter(mock_config_entry.subentries.values()))
+    hass.config_entries.async_update_subentry(
+        mock_config_entry, subentry, data=current_options
+    )
+    await hass.async_block_till_done()
+    subentry_flow = await mock_config_entry.start_subentry_reconfigure_flow(
+        hass, subentry.subentry_id
+    )
+    assert subentry_flow["step_id"] == "init"
 
     for step_options in new_options:
-        assert options["type"] == FlowResultType.FORM
+        assert subentry_flow["type"] == FlowResultType.FORM
 
         # Test that current options are showed as suggested values:
-        for key in options["data_schema"].schema:
+        for key in subentry_flow["data_schema"].schema:
             if (
                 isinstance(key.description, dict)
                 and "suggested_value" in key.description
@@ -523,38 +620,42 @@ async def test_options_switching(
                 assert key.description["suggested_value"] == current_option
 
         # Configure current step
-        options = await hass.config_entries.options.async_configure(
-            options["flow_id"],
+        subentry_flow = await hass.config_entries.subentries.async_configure(
+            subentry_flow["flow_id"],
             step_options,
         )
         await hass.async_block_till_done()
 
-    assert options["type"] is FlowResultType.CREATE_ENTRY
-    assert options["data"] == expected_options
+    assert subentry_flow["type"] is FlowResultType.ABORT
+    assert subentry_flow["reason"] == "reconfigure_successful"
+    assert subentry.data == expected_options
 
 
-async def test_options_web_search_user_location(
+async def test_subentry_web_search_user_location(
     hass: HomeAssistant, mock_config_entry, mock_init_component
 ) -> None:
     """Test fetching user location."""
-    options = await hass.config_entries.options.async_init(mock_config_entry.entry_id)
-    assert options["type"] == FlowResultType.FORM
-    assert options["step_id"] == "init"
+    subentry = next(iter(mock_config_entry.subentries.values()))
+    subentry_flow = await mock_config_entry.start_subentry_reconfigure_flow(
+        hass, subentry.subentry_id
+    )
+    assert subentry_flow["type"] == FlowResultType.FORM
+    assert subentry_flow["step_id"] == "init"
 
     # Configure initial step
-    options = await hass.config_entries.options.async_configure(
-        options["flow_id"],
+    subentry_flow = await hass.config_entries.subentries.async_configure(
+        subentry_flow["flow_id"],
         {
             CONF_RECOMMENDED: False,
             CONF_PROMPT: "Speak like a pirate",
         },
     )
-    assert options["type"] == FlowResultType.FORM
-    assert options["step_id"] == "advanced"
+    assert subentry_flow["type"] == FlowResultType.FORM
+    assert subentry_flow["step_id"] == "advanced"
 
     # Configure advanced step
-    options = await hass.config_entries.options.async_configure(
-        options["flow_id"],
+    subentry_flow = await hass.config_entries.subentries.async_configure(
+        subentry_flow["flow_id"],
         {
             CONF_TEMPERATURE: 1.0,
             CONF_CHAT_MODEL: RECOMMENDED_CHAT_MODEL,
@@ -563,8 +664,8 @@ async def test_options_web_search_user_location(
         },
     )
     await hass.async_block_till_done()
-    assert options["type"] == FlowResultType.FORM
-    assert options["step_id"] == "model"
+    assert subentry_flow["type"] == FlowResultType.FORM
+    assert subentry_flow["step_id"] == "model"
 
     hass.config.country = "US"
     hass.config.time_zone = "America/Los_Angeles"
@@ -601,8 +702,8 @@ async def test_options_web_search_user_location(
         )
 
         # Configure model step
-        options = await hass.config_entries.options.async_configure(
-            options["flow_id"],
+        subentry_flow = await hass.config_entries.subentries.async_configure(
+            subentry_flow["flow_id"],
             {
                 CONF_WEB_SEARCH: True,
                 CONF_WEB_SEARCH_CONTEXT_SIZE: "medium",
@@ -614,8 +715,9 @@ async def test_options_web_search_user_location(
         mock_create.call_args.kwargs["input"][0]["content"] == "Where are the following"
         " coordinates located: (37.7749, -122.4194)?"
     )
-    assert options["type"] is FlowResultType.CREATE_ENTRY
-    assert options["data"] == {
+    assert subentry_flow["type"] is FlowResultType.ABORT
+    assert subentry_flow["reason"] == "reconfigure_successful"
+    assert subentry.data == {
         CONF_RECOMMENDED: False,
         CONF_PROMPT: "Speak like a pirate",
         CONF_TEMPERATURE: 1.0,
diff --git a/tests/components/openai_conversation/test_conversation.py b/tests/components/openai_conversation/test_conversation.py
index 99559cb3b61..8621465bd14 100644
--- a/tests/components/openai_conversation/test_conversation.py
+++ b/tests/components/openai_conversation/test_conversation.py
@@ -153,20 +153,18 @@ async def test_entity(
     mock_init_component,
 ) -> None:
     """Test entity properties."""
-    state = hass.states.get("conversation.openai")
+    state = hass.states.get("conversation.openai_conversation")
     assert state
     assert state.attributes["supported_features"] == 0
 
-    hass.config_entries.async_update_entry(
+    hass.config_entries.async_update_subentry(
         mock_config_entry,
-        options={
-            **mock_config_entry.options,
-            CONF_LLM_HASS_API: "assist",
-        },
+        next(iter(mock_config_entry.subentries.values())),
+        data={CONF_LLM_HASS_API: "assist"},
     )
     await hass.config_entries.async_reload(mock_config_entry.entry_id)
 
-    state = hass.states.get("conversation.openai")
+    state = hass.states.get("conversation.openai_conversation")
     assert state
     assert (
         state.attributes["supported_features"]
@@ -261,7 +259,7 @@ async def test_incomplete_response(
         "Please tell me a big story",
         "mock-conversation-id",
         Context(),
-        agent_id="conversation.openai",
+        agent_id="conversation.openai_conversation",
     )
 
     assert result.response.response_type == intent.IntentResponseType.ERROR, result
@@ -285,7 +283,7 @@ async def test_incomplete_response(
         "please tell me a big story",
         "mock-conversation-id",
         Context(),
-        agent_id="conversation.openai",
+        agent_id="conversation.openai_conversation",
     )
 
     assert result.response.response_type == intent.IntentResponseType.ERROR, result
@@ -324,7 +322,7 @@ async def test_failed_response(
         "next natural number please",
         "mock-conversation-id",
         Context(),
-        agent_id="conversation.openai",
+        agent_id="conversation.openai_conversation",
     )
 
     assert result.response.response_type == intent.IntentResponseType.ERROR, result
@@ -583,7 +581,7 @@ async def test_function_call(
         "Please call the test function",
         mock_chat_log.conversation_id,
         Context(),
-        agent_id="conversation.openai",
+        agent_id="conversation.openai_conversation",
     )
 
     assert mock_create_stream.call_args.kwargs["input"][2] == {
@@ -630,7 +628,7 @@ async def test_function_call_without_reasoning(
         "Please call the test function",
         mock_chat_log.conversation_id,
         Context(),
-        agent_id="conversation.openai",
+        agent_id="conversation.openai_conversation",
     )
 
     assert result.response.response_type == intent.IntentResponseType.ACTION_DONE
@@ -686,7 +684,7 @@ async def test_function_call_invalid(
             "Please call the test function",
             "mock-conversation-id",
             Context(),
-            agent_id="conversation.openai",
+            agent_id="conversation.openai_conversation",
         )
 
 
@@ -720,7 +718,7 @@ async def test_assist_api_tools_conversion(
     ]
 
     await conversation.async_converse(
-        hass, "hello", None, Context(), agent_id="conversation.openai"
+        hass, "hello", None, Context(), agent_id="conversation.openai_conversation"
     )
 
     tools = mock_create_stream.mock_calls[0][2]["tools"]
@@ -735,10 +733,12 @@ async def test_web_search(
     mock_chat_log: MockChatLog,  # noqa: F811
 ) -> None:
     """Test web_search_tool."""
-    hass.config_entries.async_update_entry(
+    subentry = next(iter(mock_config_entry.subentries.values()))
+    hass.config_entries.async_update_subentry(
         mock_config_entry,
-        options={
-            **mock_config_entry.options,
+        subentry,
+        data={
+            **subentry.data,
             CONF_WEB_SEARCH: True,
             CONF_WEB_SEARCH_CONTEXT_SIZE: "low",
             CONF_WEB_SEARCH_USER_LOCATION: True,
@@ -764,7 +764,7 @@ async def test_web_search(
         "What's on the latest news?",
         mock_chat_log.conversation_id,
         Context(),
-        agent_id="conversation.openai",
+        agent_id="conversation.openai_conversation",
     )
 
     assert mock_create_stream.mock_calls[0][2]["tools"] == [
diff --git a/tests/components/openai_conversation/test_init.py b/tests/components/openai_conversation/test_init.py
index b4f816707e9..d209554e8d3 100644
--- a/tests/components/openai_conversation/test_init.py
+++ b/tests/components/openai_conversation/test_init.py
@@ -15,8 +15,10 @@ from openai.types.responses import Response, ResponseOutputMessage, ResponseOutp
 import pytest
 
 from homeassistant.components.openai_conversation import CONF_FILENAMES
+from homeassistant.components.openai_conversation.const import DOMAIN
 from homeassistant.core import HomeAssistant
 from homeassistant.exceptions import HomeAssistantError, ServiceValidationError
+from homeassistant.helpers import device_registry as dr, entity_registry as er
 from homeassistant.setup import async_setup_component
 
 from tests.common import MockConfigEntry
@@ -536,3 +538,271 @@ async def test_generate_content_service_error(
             blocking=True,
             return_response=True,
         )
+
+
+async def test_migration_from_v1_to_v2(
+    hass: HomeAssistant,
+    device_registry: dr.DeviceRegistry,
+    entity_registry: er.EntityRegistry,
+) -> None:
+    """Test migration from version 1 to version 2."""
+    # Create a v1 config entry with conversation options and an entity
+    OPTIONS = {
+        "recommended": True,
+        "llm_hass_api": ["assist"],
+        "prompt": "You are a helpful assistant",
+        "chat_model": "gpt-4o-mini",
+    }
+    mock_config_entry = MockConfigEntry(
+        domain=DOMAIN,
+        data={"api_key": "1234"},
+        options=OPTIONS,
+        version=1,
+        title="ChatGPT",
+    )
+    mock_config_entry.add_to_hass(hass)
+
+    device = device_registry.async_get_or_create(
+        config_entry_id=mock_config_entry.entry_id,
+        identifiers={(DOMAIN, mock_config_entry.entry_id)},
+        name=mock_config_entry.title,
+        manufacturer="OpenAI",
+        model="ChatGPT",
+        entry_type=dr.DeviceEntryType.SERVICE,
+    )
+    entity = entity_registry.async_get_or_create(
+        "conversation",
+        DOMAIN,
+        mock_config_entry.entry_id,
+        config_entry=mock_config_entry,
+        device_id=device.id,
+        suggested_object_id="google_generative_ai_conversation",
+    )
+
+    # Run migration
+    with patch(
+        "homeassistant.components.openai_conversation.async_setup_entry",
+        return_value=True,
+    ):
+        await hass.config_entries.async_setup(mock_config_entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert mock_config_entry.version == 2
+    assert mock_config_entry.data == {"api_key": "1234"}
+    assert mock_config_entry.options == {}
+
+    assert len(mock_config_entry.subentries) == 1
+
+    subentry = next(iter(mock_config_entry.subentries.values()))
+    assert subentry.unique_id is None
+    assert subentry.title == "ChatGPT"
+    assert subentry.subentry_type == "conversation"
+    assert subentry.data == OPTIONS
+
+    migrated_entity = entity_registry.async_get(entity.entity_id)
+    assert migrated_entity is not None
+    assert migrated_entity.config_entry_id == mock_config_entry.entry_id
+    assert migrated_entity.config_subentry_id == subentry.subentry_id
+    assert migrated_entity.unique_id == subentry.subentry_id
+
+    # Check device migration
+    assert not device_registry.async_get_device(
+        identifiers={(DOMAIN, mock_config_entry.entry_id)}
+    )
+    assert (
+        migrated_device := device_registry.async_get_device(
+            identifiers={(DOMAIN, subentry.subentry_id)}
+        )
+    )
+    assert migrated_device.identifiers == {(DOMAIN, subentry.subentry_id)}
+    assert migrated_device.id == device.id
+
+
+async def test_migration_from_v1_to_v2_with_multiple_keys(
+    hass: HomeAssistant,
+    device_registry: dr.DeviceRegistry,
+    entity_registry: er.EntityRegistry,
+) -> None:
+    """Test migration from version 1 to version 2 with different API keys."""
+    # Create two v1 config entries with different API keys
+    options = {
+        "recommended": True,
+        "llm_hass_api": ["assist"],
+        "prompt": "You are a helpful assistant",
+        "chat_model": "gpt-4o-mini",
+    }
+    mock_config_entry = MockConfigEntry(
+        domain=DOMAIN,
+        data={"api_key": "1234"},
+        options=options,
+        version=1,
+        title="ChatGPT 1",
+    )
+    mock_config_entry.add_to_hass(hass)
+    mock_config_entry_2 = MockConfigEntry(
+        domain=DOMAIN,
+        data={"api_key": "12345"},
+        options=options,
+        version=1,
+        title="ChatGPT 2",
+    )
+    mock_config_entry_2.add_to_hass(hass)
+
+    device = device_registry.async_get_or_create(
+        config_entry_id=mock_config_entry.entry_id,
+        identifiers={(DOMAIN, mock_config_entry.entry_id)},
+        name=mock_config_entry.title,
+        manufacturer="OpenAI",
+        model="ChatGPT 1",
+        entry_type=dr.DeviceEntryType.SERVICE,
+    )
+    entity_registry.async_get_or_create(
+        "conversation",
+        DOMAIN,
+        mock_config_entry.entry_id,
+        config_entry=mock_config_entry,
+        device_id=device.id,
+        suggested_object_id="chatgpt_1",
+    )
+
+    device_2 = device_registry.async_get_or_create(
+        config_entry_id=mock_config_entry_2.entry_id,
+        identifiers={(DOMAIN, mock_config_entry_2.entry_id)},
+        name=mock_config_entry_2.title,
+        manufacturer="OpenAI",
+        model="ChatGPT 2",
+        entry_type=dr.DeviceEntryType.SERVICE,
+    )
+    entity_registry.async_get_or_create(
+        "conversation",
+        DOMAIN,
+        mock_config_entry_2.entry_id,
+        config_entry=mock_config_entry_2,
+        device_id=device_2.id,
+        suggested_object_id="chatgpt_2",
+    )
+
+    # Run migration
+    with patch(
+        "homeassistant.components.openai_conversation.async_setup_entry",
+        return_value=True,
+    ):
+        await hass.config_entries.async_setup(mock_config_entry.entry_id)
+        await hass.async_block_till_done()
+        await hass.async_block_till_done()
+
+    entries = hass.config_entries.async_entries(DOMAIN)
+    assert len(entries) == 2
+
+    for idx, entry in enumerate(entries):
+        assert entry.version == 2
+        assert not entry.options
+        assert len(entry.subentries) == 1
+        subentry = list(entry.subentries.values())[0]
+        assert subentry.subentry_type == "conversation"
+        assert subentry.data == options
+        assert subentry.title == f"ChatGPT {idx + 1}"
+
+        dev = device_registry.async_get_device(
+            identifiers={(DOMAIN, list(entry.subentries.values())[0].subentry_id)}
+        )
+        assert dev is not None
+
+
+async def test_migration_from_v1_to_v2_with_same_keys(
+    hass: HomeAssistant,
+    device_registry: dr.DeviceRegistry,
+    entity_registry: er.EntityRegistry,
+) -> None:
+    """Test migration from version 1 to version 2 with same API keys consolidates entries."""
+    # Create two v1 config entries with the same API key
+    options = {
+        "recommended": True,
+        "llm_hass_api": ["assist"],
+        "prompt": "You are a helpful assistant",
+        "chat_model": "gpt-4o-mini",
+    }
+    mock_config_entry = MockConfigEntry(
+        domain=DOMAIN,
+        data={"api_key": "1234"},
+        options=options,
+        version=1,
+        title="ChatGPT",
+    )
+    mock_config_entry.add_to_hass(hass)
+    mock_config_entry_2 = MockConfigEntry(
+        domain=DOMAIN,
+        data={"api_key": "1234"},  # Same API key
+        options=options,
+        version=1,
+        title="ChatGPT 2",
+    )
+    mock_config_entry_2.add_to_hass(hass)
+
+    device = device_registry.async_get_or_create(
+        config_entry_id=mock_config_entry.entry_id,
+        identifiers={(DOMAIN, mock_config_entry.entry_id)},
+        name=mock_config_entry.title,
+        manufacturer="OpenAI",
+        model="ChatGPT",
+        entry_type=dr.DeviceEntryType.SERVICE,
+    )
+    entity_registry.async_get_or_create(
+        "conversation",
+        DOMAIN,
+        mock_config_entry.entry_id,
+        config_entry=mock_config_entry,
+        device_id=device.id,
+        suggested_object_id="chatgpt",
+    )
+
+    device_2 = device_registry.async_get_or_create(
+        config_entry_id=mock_config_entry_2.entry_id,
+        identifiers={(DOMAIN, mock_config_entry_2.entry_id)},
+        name=mock_config_entry_2.title,
+        manufacturer="OpenAI",
+        model="ChatGPT",
+        entry_type=dr.DeviceEntryType.SERVICE,
+    )
+    entity_registry.async_get_or_create(
+        "conversation",
+        DOMAIN,
+        mock_config_entry_2.entry_id,
+        config_entry=mock_config_entry_2,
+        device_id=device_2.id,
+        suggested_object_id="chatgpt_2",
+    )
+
+    # Run migration
+    with patch(
+        "homeassistant.components.openai_conversation.async_setup_entry",
+        return_value=True,
+    ):
+        await hass.config_entries.async_setup(mock_config_entry.entry_id)
+        await hass.async_block_till_done()
+        await hass.async_block_till_done()
+
+    # Should have only one entry left (consolidated)
+    entries = hass.config_entries.async_entries(DOMAIN)
+    assert len(entries) == 1
+
+    entry = entries[0]
+    assert entry.version == 2
+    assert not entry.options
+    assert len(entry.subentries) == 2  # Two subentries from the two original entries
+
+    # Check both subentries exist with correct data
+    subentries = list(entry.subentries.values())
+    titles = [sub.title for sub in subentries]
+    assert "ChatGPT" in titles
+    assert "ChatGPT 2" in titles
+
+    for subentry in subentries:
+        assert subentry.subentry_type == "conversation"
+        assert subentry.data == options
+
+        # Check devices were migrated correctly
+        dev = device_registry.async_get_device(
+            identifiers={(DOMAIN, subentry.subentry_id)}
+        )
+        assert dev is not None