diff --git a/homeassistant/helpers/entity_registry.py b/homeassistant/helpers/entity_registry.py
index a0bc63786d8..5d17c0c46b1 100644
--- a/homeassistant/helpers/entity_registry.py
+++ b/homeassistant/helpers/entity_registry.py
@@ -1286,7 +1286,7 @@ class EntityRegistry(BaseRegistry):
                     categories=entity["categories"],
                     capabilities=entity["capabilities"],
                     config_entry_id=entity["config_entry_id"],
-                    created_at=entity["created_at"],
+                    created_at=datetime.fromisoformat(entity["created_at"]),
                     device_class=entity["device_class"],
                     device_id=entity["device_id"],
                     disabled_by=RegistryEntryDisabler(entity["disabled_by"])
@@ -1303,7 +1303,7 @@ class EntityRegistry(BaseRegistry):
                     id=entity["id"],
                     has_entity_name=entity["has_entity_name"],
                     labels=set(entity["labels"]),
-                    modified_at=entity["modified_at"],
+                    modified_at=datetime.fromisoformat(entity["modified_at"]),
                     name=entity["name"],
                     options=entity["options"],
                     original_device_class=entity["original_device_class"],
@@ -1335,10 +1335,10 @@ class EntityRegistry(BaseRegistry):
                 )
                 deleted_entities[key] = DeletedRegistryEntry(
                     config_entry_id=entity["config_entry_id"],
-                    created_at=entity["created_at"],
+                    created_at=datetime.fromisoformat(entity["created_at"]),
                     entity_id=entity["entity_id"],
                     id=entity["id"],
-                    modified_at=entity["modified_at"],
+                    modified_at=datetime.fromisoformat(entity["modified_at"]),
                     orphaned_timestamp=entity["orphaned_timestamp"],
                     platform=entity["platform"],
                     unique_id=entity["unique_id"],
diff --git a/tests/helpers/test_entity_registry.py b/tests/helpers/test_entity_registry.py
index afcd0d0ed2e..9b1d68c7777 100644
--- a/tests/helpers/test_entity_registry.py
+++ b/tests/helpers/test_entity_registry.py
@@ -19,6 +19,7 @@ from homeassistant.const import (
 from homeassistant.core import CoreState, HomeAssistant, callback
 from homeassistant.exceptions import MaxLengthExceeded
 from homeassistant.helpers import device_registry as dr, entity_registry as er
+from homeassistant.util.dt import utc_from_timestamp
 
 from tests.common import (
     ANY,
@@ -442,6 +443,8 @@ async def test_filter_on_load(
     assert entry_with_name.name == "registry override"
     assert entry_without_name.name is None
     assert not entry_with_name.disabled
+    assert entry_with_name.created_at == utc_from_timestamp(0)
+    assert entry_with_name.modified_at == utc_from_timestamp(0)
 
     entry_disabled_hass = registry.async_get_or_create(
         "test", "super_platform", "disabled-hass"