HMS E10 (Lt Cdr W StJ Fraser) sailed in company with HMS E5 from Yarmouth on 18 January 1915 for a patrol off Heligoland. That evening, E5 reported her position with E10 in sight on her starboard quarter. E10 patrol area was NNW of Heligoland. She was lost with all hands and listed as officially lost on 21 January 1915.
E5 later reported that E10 possibly ran into a minefield laid on 22 Dec 1914 but not known to the British at that time.