diff --git a/homeassistant/components/opentherm_gw/__init__.py b/homeassistant/components/opentherm_gw/__init__.py
index f0f5c709d0c..d8c352f3768 100644
--- a/homeassistant/components/opentherm_gw/__init__.py
+++ b/homeassistant/components/opentherm_gw/__init__.py
@@ -9,6 +9,7 @@ import pyotgw.vars as gw_vars
 from serial import SerialException
 import voluptuous as vol
 
+from homeassistant.components.climate import DOMAIN as CLIMATE_DOMAIN
 from homeassistant.config_entries import SOURCE_IMPORT, ConfigEntry
 from homeassistant.const import (
     ATTR_DATE,
@@ -27,7 +28,11 @@ from homeassistant.const import (
 )
 from homeassistant.core import HomeAssistant, ServiceCall
 from homeassistant.exceptions import ConfigEntryNotReady
-from homeassistant.helpers import config_validation as cv, device_registry as dr
+from homeassistant.helpers import (
+    config_validation as cv,
+    device_registry as dr,
+    entity_registry as er,
+)
 from homeassistant.helpers.dispatcher import async_dispatcher_send
 from homeassistant.helpers.typing import ConfigType
 
@@ -132,6 +137,18 @@ async def async_setup_entry(hass: HomeAssistant, config_entry: ConfigEntry) -> b
             },
         )
 
+    # Migration can be removed in 2025.4.0
+    ent_reg = er.async_get(hass)
+    if (
+        entity_id := ent_reg.async_get_entity_id(
+            CLIMATE_DOMAIN, DOMAIN, config_entry.data[CONF_ID]
+        )
+    ) is not None:
+        ent_reg.async_update_entity(
+            entity_id,
+            new_unique_id=f"{config_entry.data[CONF_ID]}-{OpenThermDeviceIdentifier.THERMOSTAT}-thermostat_entity",
+        )
+
     config_entry.add_update_listener(options_updated)
 
     try:
diff --git a/homeassistant/components/opentherm_gw/climate.py b/homeassistant/components/opentherm_gw/climate.py
index 795a508be12..45f1ca478f5 100644
--- a/homeassistant/components/opentherm_gw/climate.py
+++ b/homeassistant/components/opentherm_gw/climate.py
@@ -103,7 +103,6 @@ class OpenThermClimate(OpenThermEntity, ClimateEntity):
             self._attr_precision = options[CONF_READ_PRECISION]
         self._attr_target_temperature_step = options.get(CONF_SET_PRECISION)
         self.temporary_ovrd_mode = options.get(CONF_TEMPORARY_OVRD_MODE, True)
-        self._attr_unique_id = gw_hub.hub_id
 
     @callback
     def update_options(self, entry):
diff --git a/tests/components/opentherm_gw/test_init.py b/tests/components/opentherm_gw/test_init.py
index 7b9801c8280..ed829cb1986 100644
--- a/tests/components/opentherm_gw/test_init.py
+++ b/tests/components/opentherm_gw/test_init.py
@@ -12,7 +12,7 @@ from homeassistant.components.opentherm_gw.const import (
 )
 from homeassistant.const import CONF_DEVICE, CONF_ID, CONF_NAME
 from homeassistant.core import HomeAssistant
-from homeassistant.helpers import device_registry as dr
+from homeassistant.helpers import device_registry as dr, entity_registry as er
 
 from tests.common import MockConfigEntry
 
@@ -154,3 +154,36 @@ async def test_device_migration(
         )
         is not None
     )
+
+
+# Entity migration test can be removed in 2025.4.0
+async def test_climate_entity_migration(
+    hass: HomeAssistant, entity_registry: er.EntityRegistry
+) -> None:
+    """Test that the climate entity unique_id gets migrated correctly."""
+    MOCK_CONFIG_ENTRY.add_to_hass(hass)
+    entry = entity_registry.async_get_or_create(
+        domain="climate",
+        platform="opentherm_gw",
+        unique_id=MOCK_CONFIG_ENTRY.data[CONF_ID],
+    )
+
+    with (
+        patch(
+            "homeassistant.components.opentherm_gw.OpenThermGateway",
+            return_value=MagicMock(
+                connect=AsyncMock(return_value=MINIMAL_STATUS_UPD),
+                set_control_setpoint=AsyncMock(),
+                set_max_relative_mod=AsyncMock(),
+                disconnect=AsyncMock(),
+            ),
+        ),
+    ):
+        await setup.async_setup_component(hass, DOMAIN, {})
+
+    await hass.async_block_till_done()
+
+    assert (
+        entity_registry.async_get(entry.entity_id).unique_id
+        == f"{MOCK_CONFIG_ENTRY.data[CONF_ID]}-{OpenThermDeviceIdentifier.THERMOSTAT}-thermostat_entity"
+    )