SMS Ägir was the second and final member of the Odin class of coastal defense ships (Küstenpanzerschiffe) built for the German Imperial Navy. She had one sister ship, Odin. Ägir was named for the eponymous norse god, and was built by the Kaiserliche Werft Danzig shipyard between 1893 and 1896. She was armed with a main battery of three guns. She served in the German fleet throughout the 1890s and was rebuilt in 1901–1903. She served in the VI Battle Squadron after the outbreak of World War I in August 1914, but saw no action. Ägir was demobilized in 1915 and used as a tender thereafter. After the war, she was rebuilt as a merchant ship and served in this capacity until December 1929, when she was wrecked on the island of Gotland.