German submarine U-870

German submarine U-870 was a Type IXC/40 U-boat of the Nazi German Kriegsmarine built for service during the Second World War. She was ordered on 25 August 1941, and laid down on 29 April 1943 at Bremen in Germany. She was launched on 29 October 1943 and commissioned on 3 February 1944. For her two patrols, she had one commander, Korvettenkapitän Ernst Hechler, who was awarded the Knight's Cross of the Iron Cross. Over her career she claimed two warships sunk, total tonnage 1,960 tons, one warship damaged for a total tonnage 1,400 tons, and two ships a total loss, total tonnage 11,844 GRT.

On 20 December 1944, U-870 attacked a small group of landing ships, damaging the USS Fogg (DE-57) and sinking the 1,625 ton vessel USS LST-359. The U-boat was then attacked by a British aircraft from No. 220 Squadron RAF but got away, also evading two hunter-killer groups of vessels.

She was sunk on 30 March 1945 at Bremen by US bombs.