diff --git a/homeassistant/components/device_tracker/legacy.py b/homeassistant/components/device_tracker/legacy.py
index 1fdd8077728..1a2e7c854e5 100644
--- a/homeassistant/components/device_tracker/legacy.py
+++ b/homeassistant/components/device_tracker/legacy.py
@@ -14,6 +14,7 @@ from homeassistant.components.zone import async_active_zone
 from homeassistant.config import load_yaml_config_file, async_log_exception
 from homeassistant.exceptions import HomeAssistantError
 import homeassistant.helpers.config_validation as cv
+from homeassistant.helpers.entity_registry import async_get_registry
 from homeassistant.helpers.restore_state import RestoreEntity
 from homeassistant.helpers.typing import GPSType, HomeAssistantType
 from homeassistant import util
@@ -115,6 +116,7 @@ class DeviceTracker:
 
         This method is a coroutine.
         """
+        registry = await async_get_registry(self.hass)
         if mac is None and dev_id is None:
             raise HomeAssistantError('Neither mac or device id passed in')
         if mac is not None:
@@ -134,6 +136,14 @@ class DeviceTracker:
                 await device.async_update_ha_state()
             return
 
+        # Guard from calling see on entity registry entities.
+        entity_id = ENTITY_ID_FORMAT.format(dev_id)
+        if registry.async_is_registered(entity_id):
+            LOGGER.error(
+                "The see service is not supported for this entity %s",
+                entity_id)
+            return
+
         # If no device can be found, create it
         dev_id = util.ensure_unique_string(dev_id, self.devices.keys())
         device = Device(
diff --git a/tests/components/device_tracker/test_init.py b/tests/components/device_tracker/test_init.py
index 9a59855e8c1..cd518770c5b 100644
--- a/tests/components/device_tracker/test_init.py
+++ b/tests/components/device_tracker/test_init.py
@@ -3,7 +3,7 @@ from datetime import datetime, timedelta
 import json
 import logging
 import os
-from unittest.mock import call
+from unittest.mock import Mock, call
 
 from asynctest import patch
 import pytest
@@ -12,9 +12,9 @@ from homeassistant.components import zone
 import homeassistant.components.device_tracker as device_tracker
 from homeassistant.components.device_tracker import const, legacy
 from homeassistant.const import (
-    ATTR_ENTITY_ID, ATTR_ENTITY_PICTURE, ATTR_FRIENDLY_NAME, ATTR_HIDDEN,
-    ATTR_ICON, CONF_PLATFORM, STATE_HOME, STATE_NOT_HOME,
-    ATTR_LATITUDE, ATTR_LONGITUDE, ATTR_GPS_ACCURACY)
+    ATTR_ENTITY_ID, ATTR_ENTITY_PICTURE, ATTR_FRIENDLY_NAME, ATTR_GPS_ACCURACY,
+    ATTR_HIDDEN, ATTR_ICON, ATTR_LATITUDE, ATTR_LONGITUDE, CONF_PLATFORM,
+    STATE_HOME, STATE_NOT_HOME)
 from homeassistant.core import State, callback
 from homeassistant.exceptions import HomeAssistantError
 from homeassistant.helpers import discovery
@@ -23,8 +23,8 @@ from homeassistant.setup import async_setup_component
 import homeassistant.util.dt as dt_util
 
 from tests.common import (
-    assert_setup_component, async_fire_time_changed, mock_restore_cache,
-    patch_yaml_files)
+    assert_setup_component, async_fire_time_changed, mock_registry,
+    mock_restore_cache, patch_yaml_files)
 from tests.components.device_tracker import common
 
 TEST_PLATFORM = {device_tracker.DOMAIN: {CONF_PLATFORM: 'test'}}
@@ -321,6 +321,26 @@ async def test_see_service(mock_see, hass):
     assert mock_see.call_args == call(**params)
 
 
+async def test_see_service_guard_config_entry(hass, mock_device_tracker_conf):
+    """Test the guard if the device is registered in the entity registry."""
+    mock_entry = Mock()
+    dev_id = 'test'
+    entity_id = const.ENTITY_ID_FORMAT.format(dev_id)
+    mock_registry(hass, {entity_id: mock_entry})
+    devices = mock_device_tracker_conf
+    assert await async_setup_component(
+        hass, device_tracker.DOMAIN, TEST_PLATFORM)
+    params = {
+        'dev_id': dev_id,
+        'gps': [.3, .8],
+    }
+
+    common.async_see(hass, **params)
+    await hass.async_block_till_done()
+
+    assert not devices
+
+
 async def test_new_device_event_fired(hass, mock_device_tracker_conf):
     """Test that the device tracker will fire an event."""
     with assert_setup_component(1, device_tracker.DOMAIN):