 In February 1915, Agamemnon was ordered to participate in the Dardanelles Campaign. She departed Portland on 9 February, and joined the British Dardanelles Squadron at Mudros 10 days later. That was the second day of the opening bombardment of the Ottoman Turkish forts guarding the entrance to the Dardanelles and the ship immediately joined the attack. She also took part in the subsequent bombardment of the inner forts later in February. Agamemnon was hit by seven 240-millimetre (9.4-inch) shells in ten minutes on 25 February and was holed above the waterline, suffering three dead.
