SM U-12 was a German submarine, built in 1911 and sunk off Scotland in 1915. It was the first submarine to launch a plane at sea. U-12 was a Type U 9 U-boat built for the Imperial German Navy. Her construction was ordered on 15 July 1908 and her keel was laid down by Kaiserliche Werft in Danzig. She was launched on 6 May 1910 and commissioned on 13 August 1911.

A submarine aircraft carrier is a submarine equipped with aircraft for observation or attack missions. These submarines saw their most extensive use during World War II, although their operational significance remained rather small. The most famous of them were the Japanese I-400-class submarines and the French submarine Surcouf, although small numbers of similar craft were built for other nations' navies as well.