diff --git a/homeassistant/components/powerwall/__init__.py b/homeassistant/components/powerwall/__init__.py
index 8fcc56e449f9ce..5cccd54a32aab2 100644
--- a/homeassistant/components/powerwall/__init__.py
+++ b/homeassistant/components/powerwall/__init__.py
@@ -21,6 +21,7 @@
 from homeassistant.const import CONF_IP_ADDRESS, CONF_PASSWORD, Platform
 from homeassistant.core import HomeAssistant, callback
 from homeassistant.exceptions import ConfigEntryAuthFailed, ConfigEntryNotReady
+from homeassistant.helpers import device_registry as dr, entity_registry as er
 from homeassistant.helpers.aiohttp_client import async_create_clientsession
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.update_coordinator import DataUpdateCoordinator, UpdateFailed
@@ -151,7 +152,7 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
             raise ConfigEntryNotReady from err
 
     gateway_din = base_info.gateway_din
-    if gateway_din and entry.unique_id is not None and is_ip_address(entry.unique_id):
+    if entry.unique_id is not None and is_ip_address(entry.unique_id):
         hass.config_entries.async_update_entry(entry, unique_id=gateway_din)
 
     runtime_data = PowerwallRuntimeData(
@@ -178,11 +179,36 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
 
     hass.data.setdefault(DOMAIN, {})[entry.entry_id] = runtime_data
 
+    await async_migrate_entity_unique_ids(hass, entry, base_info)
+
     await hass.config_entries.async_forward_entry_setups(entry, PLATFORMS)
 
     return True
 
 
+async def async_migrate_entity_unique_ids(
+    hass: HomeAssistant, entry: ConfigEntry, base_info: PowerwallBaseInfo
+) -> None:
+    """Migrate old entity unique ids to use gateway_din."""
+    old_base_unique_id = "_".join(base_info.serial_numbers)
+    new_base_unique_id = base_info.gateway_din
+
+    dev_reg = dr.async_get(hass)
+    if device := dev_reg.async_get_device(identifiers={(DOMAIN, old_base_unique_id)}):
+        dev_reg.async_update_device(
+            device.id, new_identifiers={(DOMAIN, new_base_unique_id)}
+        )
+
+    ent_reg = er.async_get(hass)
+    for ent_entry in er.async_entries_for_config_entry(ent_reg, entry.entry_id):
+        current_unique_id = ent_entry.unique_id
+        if current_unique_id.startswith(old_base_unique_id):
+            new_unique_id = f"{new_base_unique_id}{current_unique_id.removeprefix(old_base_unique_id)}"
+            ent_reg.async_update_entity(
+                ent_entry.entity_id, new_unique_id=new_unique_id
+            )
+
+
 async def _login_and_fetch_base_info(
     power_wall: Powerwall, host: str, password: str | None
 ) -> PowerwallBaseInfo:
diff --git a/homeassistant/components/powerwall/entity.py b/homeassistant/components/powerwall/entity.py
index f0cfec2cbc585b..0ee4249a8e9105 100644
--- a/homeassistant/components/powerwall/entity.py
+++ b/homeassistant/components/powerwall/entity.py
@@ -29,8 +29,7 @@ def __init__(self, powerwall_data: PowerwallRuntimeData) -> None:
         assert coordinator is not None
         super().__init__(coordinator)
         self.power_wall = powerwall_data[POWERWALL_API]
-        # The serial numbers of the powerwalls are unique to every site
-        self.base_unique_id = "_".join(base_info.serial_numbers)
+        self.base_unique_id = base_info.gateway_din
         self._attr_device_info = DeviceInfo(
             identifiers={(DOMAIN, self.base_unique_id)},
             manufacturer=MANUFACTURER,
diff --git a/homeassistant/components/powerwall/models.py b/homeassistant/components/powerwall/models.py
index d67a21a0d538c3..65213065d0ed0c 100644
--- a/homeassistant/components/powerwall/models.py
+++ b/homeassistant/components/powerwall/models.py
@@ -21,7 +21,7 @@
 class PowerwallBaseInfo:
     """Base information for the powerwall integration."""
 
-    gateway_din: None | str
+    gateway_din: str
     site_info: SiteInfoResponse
     status: PowerwallStatusResponse
     device_type: DeviceType
diff --git a/tests/components/powerwall/test_sensor.py b/tests/components/powerwall/test_sensor.py
index a58c30f332e546..bca176386293bd 100644
--- a/tests/components/powerwall/test_sensor.py
+++ b/tests/components/powerwall/test_sensor.py
@@ -16,10 +16,10 @@
     STATE_UNKNOWN,
 )
 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
 import homeassistant.util.dt as dt_util
 
-from .mocks import _mock_powerwall_with_fixtures
+from .mocks import MOCK_GATEWAY_DIN, _mock_powerwall_with_fixtures
 
 from tests.common import MockConfigEntry, async_fire_time_changed
 
@@ -44,7 +44,7 @@ async def test_sensors(
 
     device_registry = dr.async_get(hass)
     reg_device = device_registry.async_get_device(
-        identifiers={("powerwall", "TG0123456789AB_TG9876543210BA")},
+        identifiers={("powerwall", MOCK_GATEWAY_DIN)},
     )
     assert reg_device.model == "PowerWall 2 (GW1)"
     assert reg_device.sw_version == "1.50.1 c58c2df3"
@@ -173,3 +173,64 @@ async def test_sensors_with_empty_meters(hass: HomeAssistant) -> None:
         await hass.async_block_till_done()
 
     assert hass.states.get("sensor.mysite_solar_power") is None
+
+
+async def test_unique_id_migrate(
+    hass: HomeAssistant, entity_registry_enabled_by_default: None
+) -> None:
+    """Test we can migrate unique ids of the sensors."""
+    device_registry = dr.async_get(hass)
+    ent_reg = er.async_get(hass)
+    config_entry = MockConfigEntry(domain=DOMAIN, data={CONF_IP_ADDRESS: "1.2.3.4"})
+    config_entry.add_to_hass(hass)
+
+    mock_powerwall = await _mock_powerwall_with_fixtures(hass)
+    old_unique_id = "_".join(sorted(["TG0123456789AB", "TG9876543210BA"]))
+    new_unique_id = MOCK_GATEWAY_DIN
+    device_registry.async_get_or_create(
+        config_entry_id=config_entry.entry_id,
+        identifiers={("powerwall", old_unique_id)},
+        manufacturer="Tesla",
+    )
+    old_mysite_load_power_entity = ent_reg.async_get_or_create(
+        "sensor",
+        DOMAIN,
+        unique_id=f"{old_unique_id}_load_instant_power",
+        suggested_object_id="mysite_load_power",
+        config_entry=config_entry,
+    )
+    assert old_mysite_load_power_entity.entity_id == "sensor.mysite_load_power"
+
+    with patch(
+        "homeassistant.components.powerwall.config_flow.Powerwall",
+        return_value=mock_powerwall,
+    ), patch(
+        "homeassistant.components.powerwall.Powerwall", return_value=mock_powerwall
+    ):
+        assert await hass.config_entries.async_setup(config_entry.entry_id)
+        await hass.async_block_till_done()
+
+    reg_device = device_registry.async_get_device(
+        identifiers={("powerwall", MOCK_GATEWAY_DIN)},
+    )
+    old_reg_device = device_registry.async_get_device(
+        identifiers={("powerwall", old_unique_id)},
+    )
+    assert old_reg_device is None
+    assert reg_device is not None
+
+    assert (
+        ent_reg.async_get_entity_id(
+            "sensor", DOMAIN, f"{old_unique_id}_load_instant_power"
+        )
+        is None
+    )
+    assert (
+        ent_reg.async_get_entity_id(
+            "sensor", DOMAIN, f"{new_unique_id}_load_instant_power"
+        )
+        is not None
+    )
+
+    state = hass.states.get("sensor.mysite_load_power")
+    assert state.state == "1.971"