When her refit was completed in April 1918, she was in effect the most advanced pre-dreadnought battleship in the world. She recommissioned on 16 April 1918 for service on the Northern Patrol, then transferred to the Grand Fleet on 21 August 1918, where she made full use of her updated equipment in service as a seagoing gunnery training ship based at Invergordon. After three years of this service as a training ship, "Commonwealth" paid off in February 1921. She was placed on the disposal list at Portsmouth Dockyard in April 1921 and was sold to Slough Trading Company for scrapping on 18 November 1921. She then was resold to German scrappers and towed to Germany to be broken up.