diff --git a/homeassistant/components/esphome/entity.py b/homeassistant/components/esphome/entity.py
index 15ea54422d4..37f8e738aee 100644
--- a/homeassistant/components/esphome/entity.py
+++ b/homeassistant/components/esphome/entity.py
@@ -226,6 +226,7 @@ class EsphomeEntity(EsphomeBaseEntity, Generic[_InfoT, _StateT]):
     _static_info: _InfoT
     _state: _StateT
     _has_state: bool
+    unique_id: str
 
     def __init__(
         self,
diff --git a/homeassistant/components/esphome/media_player.py b/homeassistant/components/esphome/media_player.py
index 3af6c0b2049..f18b5e7bf5c 100644
--- a/homeassistant/components/esphome/media_player.py
+++ b/homeassistant/components/esphome/media_player.py
@@ -78,7 +78,7 @@ class EsphomeMediaPlayer(
         if self._static_info.supports_pause:
             flags |= MediaPlayerEntityFeature.PAUSE | MediaPlayerEntityFeature.PLAY
         self._attr_supported_features = flags
-        self._entry_data.media_player_formats[static_info.unique_id] = cast(
+        self._entry_data.media_player_formats[self.unique_id] = cast(
             MediaPlayerInfo, static_info
         ).supported_formats
 
@@ -114,9 +114,8 @@ class EsphomeMediaPlayer(
         media_id = async_process_play_media_url(self.hass, media_id)
         announcement = kwargs.get(ATTR_MEDIA_ANNOUNCE)
         bypass_proxy = kwargs.get(ATTR_MEDIA_EXTRA, {}).get(ATTR_BYPASS_PROXY)
-
         supported_formats: list[MediaPlayerSupportedFormat] | None = (
-            self._entry_data.media_player_formats.get(self._static_info.unique_id)
+            self._entry_data.media_player_formats.get(self.unique_id)
         )
 
         if (
@@ -139,7 +138,7 @@ class EsphomeMediaPlayer(
     async def async_will_remove_from_hass(self) -> None:
         """Handle entity being removed."""
         await super().async_will_remove_from_hass()
-        self._entry_data.media_player_formats.pop(self.entity_id, None)
+        self._entry_data.media_player_formats.pop(self.unique_id, None)
 
     def _get_proxy_url(
         self,
diff --git a/tests/components/esphome/test_media_player.py b/tests/components/esphome/test_media_player.py
index e1a0cd6c348..ccc3ed3e70a 100644
--- a/tests/components/esphome/test_media_player.py
+++ b/tests/components/esphome/test_media_player.py
@@ -429,3 +429,105 @@ async def test_media_player_proxy(
         mock_async_create_proxy_url.assert_not_called()
         media_args = mock_client.media_player_command.call_args.kwargs
         assert media_args["media_url"] == media_url
+
+
+async def test_media_player_formats_reload_preserves_data(
+    hass: HomeAssistant,
+    mock_client: APIClient,
+    mock_esphome_device: MockESPHomeDeviceType,
+) -> None:
+    """Test that media player formats are properly managed on reload."""
+    # Create a media player with supported formats
+    supported_formats = [
+        MediaPlayerSupportedFormat(
+            format="mp3",
+            sample_rate=48000,
+            num_channels=2,
+            purpose=MediaPlayerFormatPurpose.DEFAULT,
+        ),
+        MediaPlayerSupportedFormat(
+            format="wav",
+            sample_rate=16000,
+            num_channels=1,
+            purpose=MediaPlayerFormatPurpose.ANNOUNCEMENT,
+            sample_bytes=2,
+        ),
+    ]
+
+    mock_device = await mock_esphome_device(
+        mock_client=mock_client,
+        entity_info=[
+            MediaPlayerInfo(
+                object_id="test_media_player",
+                key=1,
+                name="Test Media Player",
+                unique_id="test_unique_id",
+                supports_pause=True,
+                supported_formats=supported_formats,
+            )
+        ],
+        states=[
+            MediaPlayerEntityState(
+                key=1, volume=50, muted=False, state=MediaPlayerState.IDLE
+            )
+        ],
+    )
+    await hass.async_block_till_done()
+
+    # Verify entity was created
+    state = hass.states.get("media_player.test_test_media_player")
+    assert state is not None
+    assert state.state == "idle"
+
+    # Test that play_media works with proxy URL (which requires formats to be stored)
+    media_url = "http://127.0.0.1/test.mp3"
+
+    await hass.services.async_call(
+        MEDIA_PLAYER_DOMAIN,
+        SERVICE_PLAY_MEDIA,
+        {
+            ATTR_ENTITY_ID: "media_player.test_test_media_player",
+            ATTR_MEDIA_CONTENT_TYPE: MediaType.MUSIC,
+            ATTR_MEDIA_CONTENT_ID: media_url,
+        },
+        blocking=True,
+    )
+
+    # Verify the API was called with a proxy URL (contains /api/esphome/ffmpeg_proxy/)
+    mock_client.media_player_command.assert_called_once()
+    call_args = mock_client.media_player_command.call_args
+    assert "/api/esphome/ffmpeg_proxy/" in call_args.kwargs["media_url"]
+    assert ".mp3" in call_args.kwargs["media_url"]  # Should use mp3 format for default
+    assert call_args.kwargs["announcement"] is None
+
+    mock_client.media_player_command.reset_mock()
+
+    # Reload the integration
+    await hass.config_entries.async_reload(mock_device.entry.entry_id)
+    await hass.async_block_till_done()
+
+    # Verify entity still exists after reload
+    state = hass.states.get("media_player.test_test_media_player")
+    assert state is not None
+
+    # Test that play_media still works after reload with announcement
+    await hass.services.async_call(
+        MEDIA_PLAYER_DOMAIN,
+        SERVICE_PLAY_MEDIA,
+        {
+            ATTR_ENTITY_ID: "media_player.test_test_media_player",
+            ATTR_MEDIA_CONTENT_TYPE: MediaType.MUSIC,
+            ATTR_MEDIA_CONTENT_ID: media_url,
+            ATTR_MEDIA_ANNOUNCE: True,
+        },
+        blocking=True,
+    )
+
+    # Verify the API was called with a proxy URL using wav format for announcements
+    mock_client.media_player_command.assert_called_once()
+    call_args = mock_client.media_player_command.call_args
+    assert "/api/esphome/ffmpeg_proxy/" in call_args.kwargs["media_url"]
+    assert (
+        ".wav" in call_args.kwargs["media_url"]
+    )  # Should use wav format for announcement
+    assert call_args.kwargs["announcement"] is True