diff --git a/homeassistant/components/aseko_pool_live/config_flow.py b/homeassistant/components/aseko_pool_live/config_flow.py
index a07395742fe..e93eb803d62 100644
--- a/homeassistant/components/aseko_pool_live/config_flow.py
+++ b/homeassistant/components/aseko_pool_live/config_flow.py
@@ -29,7 +29,7 @@ class AsekoConfigFlow(ConfigFlow, domain=DOMAIN):
         }
     )
 
-    async def get_account_info(self, email: str, password: str) -> dict:
+    async def get_account_info(self, email: str, password: str) -> dict[str, Any]:
         """Get account info from the mobile API and the web API."""
         aseko = Aseko(email, password)
         user = await aseko.login()
@@ -70,7 +70,9 @@ class AsekoConfigFlow(ConfigFlow, domain=DOMAIN):
     async def async_store_credentials(self, info: dict[str, Any]) -> ConfigFlowResult:
         """Store validated credentials."""
 
+        await self.async_set_unique_id(info[CONF_UNIQUE_ID])
         if self.source == SOURCE_REAUTH:
+            self._abort_if_unique_id_mismatch()
             return self.async_update_reload_and_abort(
                 self._get_reauth_entry(),
                 title=info[CONF_EMAIL],
@@ -80,7 +82,6 @@ class AsekoConfigFlow(ConfigFlow, domain=DOMAIN):
                 },
             )
 
-        await self.async_set_unique_id(info[CONF_UNIQUE_ID])
         self._abort_if_unique_id_configured()
 
         return self.async_create_entry(
diff --git a/homeassistant/components/aseko_pool_live/strings.json b/homeassistant/components/aseko_pool_live/strings.json
index 9f6a99b8d12..2805b60cdfd 100644
--- a/homeassistant/components/aseko_pool_live/strings.json
+++ b/homeassistant/components/aseko_pool_live/strings.json
@@ -21,7 +21,8 @@
     },
     "abort": {
       "already_configured": "[%key:common::config_flow::abort::already_configured_account%]",
-      "reauth_successful": "[%key:common::config_flow::abort::reauth_successful%]"
+      "reauth_successful": "[%key:common::config_flow::abort::reauth_successful%]",
+      "unique_id_mismatch": "The user identifier does not match the previous identifier"
     }
   },
   "entity": {
diff --git a/tests/components/aseko_pool_live/test_config_flow.py b/tests/components/aseko_pool_live/test_config_flow.py
index eb40decf213..b307f00abbe 100644
--- a/tests/components/aseko_pool_live/test_config_flow.py
+++ b/tests/components/aseko_pool_live/test_config_flow.py
@@ -128,8 +128,9 @@ async def test_async_step_reauth_success(hass: HomeAssistant, user: User) -> Non
 
     mock_entry = MockConfigEntry(
         domain=DOMAIN,
-        unique_id="UID",
-        data={CONF_EMAIL: "aseko@example.com"},
+        unique_id="a_user_id",
+        data={CONF_EMAIL: "aseko@example.com", CONF_PASSWORD: "passw0rd"},
+        version=2,
     )
     mock_entry.add_to_hass(hass)
 
@@ -151,13 +152,61 @@ async def test_async_step_reauth_success(hass: HomeAssistant, user: User) -> Non
     ):
         result = await hass.config_entries.flow.async_configure(
             result["flow_id"],
-            {CONF_EMAIL: "aseko@example.com", CONF_PASSWORD: "passw0rd"},
+            {CONF_EMAIL: "aseko@example.com", CONF_PASSWORD: "new_password"},
         )
         await hass.async_block_till_done()
 
     assert result["type"] is FlowResultType.ABORT
     assert result["reason"] == "reauth_successful"
     assert len(mock_setup_entry.mock_calls) == 1
+    assert mock_entry.unique_id == "a_user_id"
+    assert dict(mock_entry.data) == {
+        CONF_EMAIL: "aseko@example.com",
+        CONF_PASSWORD: "new_password",
+    }
+
+
+async def test_async_step_reauth_mismatch(hass: HomeAssistant, user: User) -> None:
+    """Test mismatch reauthentication."""
+
+    mock_entry = MockConfigEntry(
+        domain=DOMAIN,
+        unique_id="UID",
+        data={CONF_EMAIL: "aseko@example.com", CONF_PASSWORD: "passw0rd"},
+        version=2,
+    )
+    mock_entry.add_to_hass(hass)
+
+    result = await mock_entry.start_reauth_flow(hass)
+
+    assert result["type"] is FlowResultType.FORM
+    assert result["step_id"] == "reauth_confirm"
+    assert result["errors"] == {}
+
+    with (
+        patch(
+            "homeassistant.components.aseko_pool_live.config_flow.Aseko.login",
+            return_value=user,
+        ),
+        patch(
+            "homeassistant.components.aseko_pool_live.async_setup_entry",
+            return_value=True,
+        ) as mock_setup_entry,
+    ):
+        result = await hass.config_entries.flow.async_configure(
+            result["flow_id"],
+            {CONF_EMAIL: "aseko@example.com", CONF_PASSWORD: "new_password"},
+        )
+        await hass.async_block_till_done()
+
+    assert result["type"] is FlowResultType.ABORT
+    assert result["reason"] == "unique_id_mismatch"
+    assert len(mock_setup_entry.mock_calls) == 0
+    assert mock_entry.unique_id == "UID"
+    assert dict(mock_entry.data) == {
+        CONF_EMAIL: "aseko@example.com",
+        CONF_PASSWORD: "passw0rd",
+    }
 
 
 @pytest.mark.parametrize(