German submarine U-10 was a Type IIB U-boat built before World War II for service in Nazi Germany's Kriegsmarine. As she was one of the first batch of boats built following the renunciation of the Treaty of Versailles, she was only capable of coastal and short cruising work. This led to her being reassigned to training duties after the Norwegian campaign of 1940 together with many of her sister boats.
After almost five years she was stricken on 1 August 1944 at Danzig (now Gdaà Âsk) and broken up.
German Type IIB submarines were enlarged versions of the original Type IIs. U-10 had a displacement of when at the surface and while submerged. Officially, the standard tonnage was , however. The U-boat had a total length of , a pressure hull length of , a beam of , a height of , and a draught of . The submarine was powered by two MWM RS 127 S four-stroke, six-cylinder diesel engines of for cruising, two Siemens-Schuckert PG VV 322/36 double-acting electric motors producing a total of for use while submerged. She had two shafts and two propellers. The boat was capable of operating at depths of up to .
The submarine had a maximum surface speed of and a maximum submerged speed of . When submerged, the boat could operate for at ; when surfaced, she could travel at . U-10 was fitted with three torpedo tubes at the bow, five torpedoes or up to twelve Type A torpedo mines, and a anti-aircraft gun. The boat had a complement of twentyfive.
U-10 was one of the first batch of submarines to be assigned to an operational unit of the Kriegsmarine, serving with the 1st U-boat Flotilla, at the time known as the Weddigen Flotilla.