In 1912, Hibernia hosted trials in naval aviation with the temporary addition of a runway to her foredeck, and the first launch of an aircraft from a vessel underway was achieved from her in early May. Later in 1912, after her experiment with aviation was completed, she and her sister ships formed the 3rd Battle Squadron. The squadron was assigned to the Grand Fleet at the beginning of World War I, and served on the Northern Patrol. In 1915 she supported the Dardanelles Campaign and provided cover for the evacuation from the Gallipoli Peninsula. On returning to the United Kingdom she was again attached to the Grand Fleet before being transferred to Nore Command in May 1916, finishing the war as an accommodation ship. She was decommissioned in 1919 and scrapped in 1922.