SM UB-70 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 29 October 1917 as SM UB-70.^{[Note 1]}

UB-70 was serving in the Mediterranean when she departed on her last patrol on 16 April 1918. She was last heard from on 5 May 1918 when she reported herself to be in the Mediterranean Sea east of Gibraltar. She was never seen or heard from again. Her entire crew of 33 men was lost.^[4]

UB-70 was built by Friedrich Krupp Germaniawerft of Kiel and following just under a year of construction, launched at Kiel on 17 August 1917. UB-70 was commissioned later that same year under the command of Kptlt. Johannes Remy. Like all Type UB III submarines, UB-70 carried 10 torpedoes and was armed with a 8.8 cm (3.46 in) deck gun. UB-70 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-70 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.

Date	Name	Nationality	Tonnage[Note 2]	Fate[5]
2 May 1918	Valdivia	France	1,794	Sunk