|Ordered||5 Jun 1941|
|Laid down||3 Sep 1942||Howaldtswerke Hamburg AG, Hamburg (werk 827)|
|Launched||18 Sep 1943|
|Commissioned||25 Oct 1943||Oblt. Guido Hyronimus|
|Successes||No ships sunk or damaged|
Sunk 7 July, 1944 in the English Channel south-west of Brighton, in position 50.32N, 00.23W, by depth charges from the Canadian destroyers HMCS Ottawa and HMCS Kootenay and the British corvette HMS Statice. 52 dead (all hands lost).
Men lost from U-boats
Unlike many other U-boats, which during their service lost men due to accidents and various other causes, U-678 did not suffer any casualties (we know of) until the time of her loss.