German submarine U-1221

German submarine U-1221 was a Type IXC/40 U-boat built for Nazi Germany's Kriegsmarine during World War II.

U-1221 was ordered in August 1941 from Deutsche Werft, AG in Hamburg under the yard number 368. Her keel was laid down on 28 October 1942 and the U-boat was launched the following year on 25 May 1943. She was commissioned into service under the command of Oberleutnant zur See Karl Kölzer (Crew 31) in the 4th U-boat Flotilla.

On 20 January 1944, Kölzer handed over command to Oblt.z.S. Paul Ackermann (Crew XII/39), who took her on her first - and only - patrol in the West Atlantic from 14 August to 27 November 1944.

During an air raid by Eighth Air Force on Kiel, U-1221 was hit by two bombs in the fore-ship on 3 April 1945. The U-boat sank immediately, taking the skeleton crew of 18 with her. Seven of her crew perished, while the rest was rescued through the stern torpedo tubes the next day.