SS Letitia was an ocean liner, built initially for service with the Anchor-Donaldson Line. She continued to serve with its successor company Donaldson Atlantic Line, and was requisitioned for service at the start of the Second World War to serve as an armed merchant cruiser. She was withdrawn from this service in 1941 and became a troop ship. She was badly damaged in 1943 and on being repaired was made a hospital ship in Canada.