German submarine U-357 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II and was sunk by British warships northwest of Ireland on 26 December 1942 on her first operational patrol.

The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of 2,800 to 3,200 metric horsepower (2,060 to 2,350 kW; 2,760 to 3,160 shp) for use while surfaced, two AEG GU 460/8-276 double-acting electric motors producing a total of 750 metric horsepower (550 kW; 740 shp) for use while submerged.

[3] When submerged, the boat could operate for 80 nautical miles (150 km; 92 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 8,500 nautical miles (15,700 km; 9,800 mi) at 10 knots (19 km/h; 12 mph).

[3] The submarine was laid down on 19 May 1940 at the Flensburger Schiffbau-Gesellschaft yard at Flensburg as yard number 476, launched on 31 March 1942 and commissioned on 18 June under the command of Kapitänleutnant Adolf Kellner.

U-357 was sunk by depth charges dropped from the British destroyers HMS Hesperus and Vanessa on 26 December 1942 northwest of Ireland.