|Ordered||15 Aug 1940|
|Laid down||15 Jul 1941||Blohm & Voss, Hamburg (werk 599)|
|Launched||31 Mar 1942|
|Commissioned||21 May 1942||Oblt. Hermann Schrüder|
|Successes||No ships sunk or damaged|
Sunk 21 Feb, 1943 in the Atlantic, in position 48.08N, 29.37W, by 6 depth charges from a British Liberator aircraft (Sqdn. 120/T). 46 dead (all hands lost).
U-623 operated with the following Wolfpacks during its career:
Drachen (22 Nov 1942 - 3 Dec 1942)
Panzer (3 Dec 1942 - 9 Dec 1942)
Ungestüm (11 Dec 1942 - 13 Dec 1942)
Raufbold (13 Dec 1942 - 18 Dec 1942)
Ritter (11 Feb 1943 - 21 Feb 1943)
Men lost from U-boats
Unlike many other U-boats, which during their service lost men due to accidents and various other causes, U-623 did not suffer any casualties (we know of) until the time of her loss.