In March 1916, HMS E5 (Lt Cdr H D Edwards) sailed for a patrol in the Heligoland Bight in company with HMS E23, E29, and H5. E5 failed to return. The last possible sighting of E5 was made by E29 during the afternoon of 6 March, 7 miles north of Juist Island. This was close to a German minefield, and it is possible that she struck a mine in this area. The exact reason for her loss, however, remains unknown.