SM UB-71 was a German Type UB III submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I. She was commissioned into the German Imperial Navy on 23 November 1917 as SM UB-71.

UB-71 was serving in the Mediterranean when she was sunk by depth charges from HMS ML413 off Menorca on 21 April 1918.

She was built by Friedrich Krupp Germaniawerft of Kiel and following just under a year of construction, launched at Kiel on 12 July 1917. UB-71 was commissioned later that same year under the command of Kptlt. Kurt Schapler. Like all Type UB III submarines, UB-71 carried 10 torpedoes and was armed with a 8.8 cm (3.46 in) deck gun. UB-71 would carry a crew of up to 3 officer and 31 men and had a cruising range of 9,090 nautical miles (16,830 km; 10,460 mi). UB-71 had a displacement of 513 t (505 long tons) while surfaced and 647 t (637 long tons) when submerged. Her engines enabled her to travel at 13.2 knots (24.4 km/h; 15.2 mph) when surfaced and 7.6 knots (14.1 km/h; 8.7 mph) when submerged.