diff --git a/homeassistant/components/owntracks/device_tracker.py b/homeassistant/components/owntracks/device_tracker.py
index 742b7c34435..b573e390a12 100644
--- a/homeassistant/components/owntracks/device_tracker.py
+++ b/homeassistant/components/owntracks/device_tracker.py
@@ -9,7 +9,7 @@ from homeassistant.const import (
     ATTR_BATTERY_LEVEL,
 )
 from homeassistant.components.device_tracker.const import (
-    ENTITY_ID_FORMAT, ATTR_SOURCE_TYPE)
+    ENTITY_ID_FORMAT, ATTR_SOURCE_TYPE, SOURCE_TYPE_GPS)
 from homeassistant.components.device_tracker.config_entry import (
     DeviceTrackerEntity
 )
@@ -127,7 +127,7 @@ class OwnTracksEntity(DeviceTrackerEntity, RestoreEntity):
     @property
     def source_type(self):
         """Return the source type, eg gps or router, of the device."""
-        return self._data.get('source_type')
+        return self._data.get('source_type', SOURCE_TYPE_GPS)
 
     @property
     def device_info(self):
diff --git a/tests/components/owntracks/test_device_tracker.py b/tests/components/owntracks/test_device_tracker.py
index 7d8d48de586..5f2bda5957a 100644
--- a/tests/components/owntracks/test_device_tracker.py
+++ b/tests/components/owntracks/test_device_tracker.py
@@ -411,6 +411,19 @@ async def test_location_update(hass, context):
     """Test the update of a location."""
     await send_message(hass, LOCATION_TOPIC, LOCATION_MESSAGE)
 
+    assert_location_source_type(hass, 'gps')
+    assert_location_latitude(hass, LOCATION_MESSAGE['lat'])
+    assert_location_accuracy(hass, LOCATION_MESSAGE['acc'])
+    assert_location_state(hass, 'outer')
+
+
+async def test_location_update_no_t_key(hass, context):
+    """Test the update of a location when message does not contain 't'."""
+    message = LOCATION_MESSAGE.copy()
+    message.pop('t')
+    await send_message(hass, LOCATION_TOPIC, message)
+
+    assert_location_source_type(hass, 'gps')
     assert_location_latitude(hass, LOCATION_MESSAGE['lat'])
     assert_location_accuracy(hass, LOCATION_MESSAGE['acc'])
     assert_location_state(hass, 'outer')