German submarine U-3506 was a Type XXI U-boat of the German Kriegsmarine during World War II. The Elektroboote submarine was laid down on 14 July 1944 at the Schichau-Werke yard at Danzig, launched on 28 August 1944, and commissioned on 16 October 1944 under the command of Kapitänleutnant Gerhard Thäter.