It is not certain how E-5 met her end.

She sailed from Harwich 4 March to carry out a patrol between Ameland and the Ems; three other submarines were also on patrol at the same time - E-29 between the Ems and Nordeney; H-5 between Horns Reef and List; E-23 to the west of 8 degrees. All were due to return to Harwich on 10 March, but E-5 failed to return.

She was last seen on the afternoon of 6 March about 7 miles to the north of Juist Island.

At 08.10 on 7 March the Seydlitz and escorting torpedo boats saw a submarine and dropped depth charges, but there was no obvious result. Later that day the Regensburg sighted a submarine further to the east of this area.

This was probably E-5.

The British presumed that she had been lost in a minefield off the western Ems.