HMS E12 was a British E class submarine built by HM Dockyard, Chatham.

During the Great War, anti-submarine nets in the Dardanelles entangled her forward hydroplanes, forcing her down to a depth of 245 feet.

[citation needed] E12 managed to surface only to come under fire by shore batteries, but avoided further damage.

British E-class submarines had fuel capacities of 50 long tons (51 t) of diesel and ranges of 3,255 miles (5,238 km; 2,829 nmi) when travelling at 10 knots (19 km/h; 12 mph).

E12 was armed with a single 4-inch QF gun mounted forward of the conning tower, and five 18 inch (450 mm) torpedo tubes, two in the bow, one either side amidships, and one in the stern; a total of 10 torpedoes were carried.