German submarine U-28 was a Type VIIA U-boat of the Nazi German Kriegsmarine during World War II. Her keel was laid down on 2 December 1935, by AG Weser of Bremen. She was launched on 14 July 1936, and commissioned into the Kriegsmarine on 12 September 1936, with Kapitänleutnant Wilhelm Ambrosius in command. Ambrosius was succeeded by nine other commanding officers over the next eight years. U-28 conducted seven war patrols between 19 August 1939 and 15 November 1940, all under the command of Kapitänleutnant Günter Kuhnke, sinking 13 ships totaling and damaging two others totaling .