She was commissioned into the German Imperial Navy on 23 March 1918 as SM UB-120.

[Note 1] UB-120 was surrendered to the British on 24 November 1918 in accordance with the requirements of the Armistice with Germany.

She was broken up in Swansea in 1922[3] She was built by AG Weser of Bremen and following just under a year of construction, launched at Bremen on 23 February 1918.

Like all Type UB III submarines, UB-120 carried 10 torpedoes and was armed with a 8.8 cm (3.46 in) deck gun.

UB-120 would carry a crew of up to 3 officer and 31 men and had a cruising range of 7,280 nautical miles (13,480 km; 8,380 mi).