diff --git a/homeassistant/components/esphome/timer_list.py b/homeassistant/components/esphome/timer_list.py
index 82c538fc01ca..a9cb54dfb7dc 100644
--- a/homeassistant/components/esphome/timer_list.py
+++ b/homeassistant/components/esphome/timer_list.py
@@ -2,7 +2,7 @@
 
 from functools import partial
 
-from aioesphomeapi import VoiceAssistantTimerEventType
+from aioesphomeapi import VoiceAssistantFeature, VoiceAssistantTimerEventType
 
 from homeassistant.components.timer_list import (
     InMemoryTimerListEntity,
@@ -46,11 +46,14 @@ async def async_setup_entry(
     entry: ESPHomeConfigEntry,
     async_add_entities: AddConfigEntryEntitiesCallback,
 ) -> None:
-    """Set up the timer list for a voice-capable ESPHome device."""
+    """Set up the timer list for a timer-capable ESPHome device."""
     entry_data = entry.runtime_data
     device_info = entry_data.device_info
     assert device_info is not None
-    if not device_info.voice_assistant_feature_flags_compat(entry_data.api_version):
+    feature_flags = device_info.voice_assistant_feature_flags_compat(
+        entry_data.api_version
+    )
+    if not (feature_flags & VoiceAssistantFeature.TIMERS):
         return
 
     mac = device_info.mac_address
diff --git a/homeassistant/components/timer_list/local.py b/homeassistant/components/timer_list/local.py
index 3cbb309ef72b..739407cc4cd3 100644
--- a/homeassistant/components/timer_list/local.py
+++ b/homeassistant/components/timer_list/local.py
@@ -101,6 +101,9 @@ class InMemoryTimerListEntity(TimerListEntity):
     async def async_cancel_timer(self, timer_id: str) -> None:
         """Cancel a timer, archiving it in the ``cancelled`` state."""
         timer = self._get_timer(timer_id)
+        if timer.status in _FINISHED_STATUSES:
+            # Already archived (finished or cancelled); nothing to cancel.
+            return
         self._unschedule(timer_id)
         timer.status = TimerStatus.CANCELLED
         timer.finishes_at = None
diff --git a/tests/components/cloud/snapshots/test_http_api.ambr b/tests/components/cloud/snapshots/test_http_api.ambr
index 72b13befc4ce..905331d7ca82 100644
--- a/tests/components/cloud/snapshots/test_http_api.ambr
+++ b/tests/components/cloud/snapshots/test_http_api.ambr
@@ -21,7 +21,7 @@
   
   ## Active Integrations
   
-  Built-in integrations: 23
+  Built-in integrations: 25
   Custom integrations: 1
   
   <details><summary>Built-in integrations</summary>
@@ -48,9 +48,11 @@
   repairs | Repairs
   stt | Speech-to-text (STT)
   system_health | System Health
+  timer_list | Timer list
   tts | Text-to-speech (TTS)
   web_rtc | WebRTC
   webhook | Webhook
+  websocket_api | Home Assistant WebSocket API
   
   </details>
   
@@ -157,7 +159,7 @@
   
   ## Active Integrations
   
-  Built-in integrations: 23
+  Built-in integrations: 25
   Custom integrations: 0
   
   <details><summary>Built-in integrations</summary>
@@ -184,9 +186,11 @@
   repairs | Repairs
   stt | Speech-to-text (STT)
   system_health | System Health
+  timer_list | Timer list
   tts | Text-to-speech (TTS)
   web_rtc | WebRTC
   webhook | Webhook
+  websocket_api | Home Assistant WebSocket API
   
   </details>
   
diff --git a/tests/components/esphome/test_assist_satellite.py b/tests/components/esphome/test_assist_satellite.py
index 7cb8d446324d..8a21f87f87e2 100644
--- a/tests/components/esphome/test_assist_satellite.py
+++ b/tests/components/esphome/test_assist_satellite.py
@@ -833,6 +833,24 @@ async def test_timer_events(
     )
 
 
+async def test_no_timer_list_without_timers_flag(
+    hass: HomeAssistant,
+    device_registry: dr.DeviceRegistry,
+    mock_client: APIClient,
+    mock_esphome_device: MockESPHomeDeviceType,
+) -> None:
+    """Test a voice device without the TIMERS flag gets no timer list entity."""
+    await mock_esphome_device(
+        mock_client=mock_client,
+        device_info={
+            "voice_assistant_feature_flags": VoiceAssistantFeature.VOICE_ASSISTANT
+        },
+    )
+    await hass.async_block_till_done()
+
+    assert hass.states.async_entity_ids("timer_list") == []
+
+
 async def test_unknown_timer_event(
     hass: HomeAssistant,
     device_registry: dr.DeviceRegistry,
diff --git a/tests/components/timer_list/test_init.py b/tests/components/timer_list/test_init.py
index dd688a73c5cf..154e774ad70f 100644
--- a/tests/components/timer_list/test_init.py
+++ b/tests/components/timer_list/test_init.py
@@ -172,6 +172,25 @@ async def test_cancel_timer_archives_timer(hass: HomeAssistant) -> None:
     assert timers[0]["status"] == "cancelled"
 
 
+@pytest.mark.usefixtures("test_entity")
+async def test_cancel_already_archived_timer_is_noop(
+    hass: HomeAssistant, freezer: FrozenDateTimeFactory
+) -> None:
+    """Test cancelling an already-archived timer does not rewrite it."""
+    timer_id = await _start_timer(hass)
+    await _call(hass, "cancel_timer", timer_id=timer_id)
+    finished_at = (await _get_timers(hass))[0]["finished_at"]
+
+    # Cancelling again must not refresh the timestamp or re-fire a change
+    freezer.tick(timedelta(seconds=5))
+    await _call(hass, "cancel_timer", timer_id=timer_id)
+
+    timers = await _get_timers(hass)
+    assert len(timers) == 1
+    assert timers[0]["status"] == "cancelled"
+    assert timers[0]["finished_at"] == finished_at
+
+
 @pytest.mark.usefixtures("test_entity")
 async def test_archive_limit_evicts_oldest(
     hass: HomeAssistant, freezer: FrozenDateTimeFactory