German submarine U-638

German submarine U-638 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II. She was laid down on 16 October 1941 by Blohm & Voss, Hamburg as yard number 614, launched on 8 July 1942 and commissioned on 3 September 1942 under Kapitänleutnant Oskar Staudinger.

Service History
The boat's career began with training at 5th U-boat Flotilla on 3 September 1942, followed by active service on 1 February 1943 as part of the 9th Flotilla for the remainder of her service.

In three patrols she sank one merchant ship, for a total of and one ship damaged.

Wolfpacks
U-638 took part in four wolfpacks, namely
 * Burggraf (26–28 February 1943)
 * Wildfang (28 February – 5 March 1943)
 * Raubgraf (7–15 March 1943)
 * Amsel 1 (3–5 May 1943)

Fate
U-638 was sunk on 5 May 1943 in the North Atlantic in position 54.2°N, -44.08333°W, by depth charges from HMS Sunflower. All hands were lost.