In February 1915, "Dartmouth" was sent to join the forces operating off the Dardanelles in support of the Gallipoli Campaign. On 15 March she suffered a boiler explosion that killed 15 of her crew. Despite this damage, "Dartmouth" continued operations, and on 18 March "Dartmouth" patrolled off the West coast of the Gallipoli peninsula while a final attempt was made by the battleships of the fleet to force the straits during daylight. The attack was a failure, with three battleships sunk by mines, and several more ships heavily damages by mines or by Turkish gunfire. "Dartmouth" escorted the battlecruiser , badly damaged by striking a mine, to Tenedos. On 25 April, the Allies landed troops at Anzac Cove and Cape Helles on the Gallipoli peninsula, with "Dartmouth" taking part in a diversionary simulated landing further north, at Bulair.