diff --git a/homeassistant/components/sonos/switch.py b/homeassistant/components/sonos/switch.py
index f2108697684..2770b7461f8 100644
--- a/homeassistant/components/sonos/switch.py
+++ b/homeassistant/components/sonos/switch.py
@@ -91,6 +91,9 @@ async def async_setup_entry(
     """Set up Sonos from a config entry."""
 
     async def _async_create_alarms(speaker: SonosSpeaker, alarm_ids: list[str]) -> None:
+        async_migrate_alarm_unique_ids(
+            hass, config_entry, speaker.household_id, alarm_ids
+        )
         entities = []
         created_alarms = (
             hass.data[DATA_SONOS].alarms[speaker.household_id].created_alarm_ids
@@ -211,7 +214,7 @@ class SonosAlarmEntity(SonosEntity, SwitchEntity):
     def __init__(self, alarm_id: str, speaker: SonosSpeaker) -> None:
         """Initialize the switch."""
         super().__init__(speaker)
-        self._attr_unique_id = f"{SONOS_DOMAIN}-{alarm_id}"
+        self._attr_unique_id = f"alarm-{speaker.household_id}:{alarm_id}"
         self.alarm_id = alarm_id
         self.household_id = speaker.household_id
         self.entity_id = ENTITY_ID_FORMAT.format(f"sonos_alarm_{self.alarm_id}")
@@ -357,6 +360,43 @@ class SonosAlarmEntity(SonosEntity, SwitchEntity):
             _LOGGER.error("Could not update %s: %s", self.entity_id, exc)
 
 
+@callback
+def async_migrate_alarm_unique_ids(
+    hass: HomeAssistant,
+    config_entry: ConfigEntry,
+    household_id: str,
+    alarm_ids: list[str],
+) -> None:
+    """Migrate alarm switch unique_ids in the entity registry to the new format."""
+    entity_registry = er.async_get(hass)
+    registry_entries = er.async_entries_for_config_entry(
+        entity_registry, config_entry.entry_id
+    )
+
+    alarm_entries = [
+        (entry.unique_id, entry)
+        for entry in registry_entries
+        if entry.domain == Platform.SWITCH and entry.original_icon == "mdi:alarm"
+    ]
+
+    for old_unique_id, alarm_entry in alarm_entries:
+        if ":" in old_unique_id:
+            continue
+
+        entry_alarm_id = old_unique_id.split("-")[-1]
+        if entry_alarm_id in alarm_ids:
+            new_unique_id = f"alarm-{household_id}:{entry_alarm_id}"
+            _LOGGER.debug(
+                "Migrating unique_id for %s from %s to %s",
+                alarm_entry.entity_id,
+                old_unique_id,
+                new_unique_id,
+            )
+            entity_registry.async_update_entity(
+                alarm_entry.entity_id, new_unique_id=new_unique_id
+            )
+
+
 @callback
 def async_migrate_speech_enhancement_entity_unique_id(
     hass: HomeAssistant,