German submarine U-3523 was a Type XXI U-boat (one of the "Elektroboote") of Nazi Germany's Kriegsmarine, built for service in World War II.

She was ordered on 6 November 1943, and was laid down on 7 October 1944 at F Schichau GmbH, Danzig, as yard number 1668.

She was launched on 14 December 1944, and commissioned under the command of Oberleutnant zur See Willi Müller on 23 January 1945.

[2] The wreck was thought to be located at 57°52′N 10°49′E / 57.867°N 10.817°E / 57.867; 10.817,[2] however, in April 2018, it was found by Sea War Museum Jutland, Thyborøn, 9 nautical miles (17 km; 10 mi) further west.

The entire fore part of the boat is buried in the seabed while its stern rises 20 metres (66 ft) above the bottom.