German submarine U-673 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II. The submarine was laid down on 20 January 1942 at the Howaldtswerke yard at Hamburg, launched on 27 February 1943, and commissioned on 8 May 1943 under the command of Oberleutnant zur See Gerhard Haelbich. Attached to 5th U-boat Flotilla based at Kiel, U-673 completed her training period on 31 May 1944 and was assigned to front-line service.