diff --git a/homeassistant/components/sonos/diagnostics.py b/homeassistant/components/sonos/diagnostics.py
index fda96b86215..96ffeb1df2a 100644
--- a/homeassistant/components/sonos/diagnostics.py
+++ b/homeassistant/components/sonos/diagnostics.py
@@ -65,17 +65,17 @@ async def async_get_config_entry_diagnostics(
 
 async def async_get_device_diagnostics(
     hass: HomeAssistant, config_entry: ConfigEntry, device: DeviceEntry
-) -> dict[str, Any] | None:
+) -> dict[str, Any]:
     """Return diagnostics for a device."""
     uid = next(
         (identifier[1] for identifier in device.identifiers if identifier[0] == DOMAIN),
         None,
     )
     if uid is None:
-        return None
+        return {}
 
     if (speaker := hass.data[DATA_SONOS].discovered.get(uid)) is None:
-        return None
+        return {}
 
     return await async_generate_speaker_info(hass, speaker)