|Ordered||6 Nov 1943|
|Laid down||24 Sep 1944||F Schichau GmbH, Danzig (werk 1666)|
|Launched||3 Dec 1944|
|Commissioned||14 Jan 1945||Oblt. Günther Keller|
|Successes||No ships sunk or damaged|
Scuttled on 2 May 1945 at Travemünde. Wreck broken up.
Men lost from U-boats
Unlike many other U-boats, which during their service lost men due to accidents and various other causes, U-3521 did not suffer any casualties (we know of) until the time of her loss.