HMS D2 sailed from Harwich on 22 November 1914 in company with HMS E5 and HMS E15 for a patrol in the North Sea. On the first night of the patrol, the commanding officer, Lt Cdr A G Jameson, was lost overboard off Great Yarmouth in very bad weather.
D2 returned to harbour and three days later, under the command of Lt Cdr Clement Head, D2 sailed for a patrol off the German coast but failed to return. It is believed that D2 was trapped in shallow water off the Estuary of the River Ems and was destroyed by a German Torpedo Boat off the Western Ems on 25 November or thereabouts.
HMS D2 was officially reported lost on 1 December.