"Canopus" was transferred to the Mediterranean in early 1915 for the Dardanelles Campaign. She participated in major attacks on the Ottoman coastal fortifications defending the Dardanelles in March 1915, but the British and French fleets proved incapable of forcing the straits. After the Gallipoli Campaign ended with the withdrawal of Allied forces in January 1916, "Canopus" patrolled the eastern Mediterranean, but saw no further action. She was removed from service in April 1916 and was converted into a barracks ship in early 1918. After the war, the ship was broken up in 1920.