diff --git a/homeassistant/components/opentherm_gw/__init__.py b/homeassistant/components/opentherm_gw/__init__.py
index 8a0a2412c25b89790740628154f04a86980a3b26..87da159872dd0bb07a11ba2eb5c74c67305cfdf0 100644
--- a/homeassistant/components/opentherm_gw/__init__.py
+++ b/homeassistant/components/opentherm_gw/__init__.py
@@ -9,7 +9,6 @@ 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 ConfigEntry
 from homeassistant.const import (
     ATTR_DATE,
@@ -25,11 +24,7 @@ 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,
-    entity_registry as er,
-)
+from homeassistant.helpers import config_validation as cv, device_registry as dr
 from homeassistant.helpers.dispatcher import async_dispatcher_send
 
 from .const import (
@@ -87,18 +82,6 @@ async def async_setup_entry(hass: HomeAssistant, config_entry: ConfigEntry) -> b
     gateway = OpenThermGatewayHub(hass, config_entry)
     hass.data[DATA_OPENTHERM_GW][DATA_GATEWAYS][config_entry.data[CONF_ID]] = gateway
 
-    # 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/tests/components/opentherm_gw/test_init.py b/tests/components/opentherm_gw/test_init.py
index e97e6d87f7cdf6415ff1ddb6828995ed63b27915..84629137ce1ffb95802f852cec2a5ebeac1df359 100644
--- a/tests/components/opentherm_gw/test_init.py
+++ b/tests/components/opentherm_gw/test_init.py
@@ -8,9 +8,8 @@ from homeassistant.components.opentherm_gw.const import (
     DOMAIN,
     OpenThermDeviceIdentifier,
 )
-from homeassistant.const import CONF_ID
 from homeassistant.core import HomeAssistant
-from homeassistant.helpers import device_registry as dr, entity_registry as er
+from homeassistant.helpers import device_registry as dr
 
 from .conftest import MOCK_GATEWAY_ID, VERSION_TEST
 
@@ -69,29 +68,3 @@ async def test_device_registry_update(
     )
     assert gw_dev is not None
     assert gw_dev.sw_version == VERSION_NEW
-
-
-# Entity migration test can be removed in 2025.4.0
-async def test_climate_entity_migration(
-    hass: HomeAssistant,
-    entity_registry: er.EntityRegistry,
-    mock_config_entry: MockConfigEntry,
-    mock_pyotgw: MagicMock,
-) -> 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],
-    )
-
-    await hass.config_entries.async_setup(mock_config_entry.entry_id)
-    await hass.async_block_till_done()
-
-    updated_entry = entity_registry.async_get(entry.entity_id)
-    assert updated_entry is not None
-    assert (
-        updated_entry.unique_id
-        == f"{mock_config_entry.data[CONF_ID]}-{OpenThermDeviceIdentifier.THERMOSTAT}-thermostat_entity"
-    )