She was commissioned into the German Imperial Navy on 4 March 1918 as SM UB-122.

[Note 1] UB-122 was surrendered to the Allies at Harwich on 20 November 1918 in accordance with the requirements of the Armistice with Germany.

Having been exhibited at Southampton in December 1918, she was then laid up at Portsmouth until scuttled in the English Channel on 1 July 1921.

Like all Type UB III submarines, UB-122 carried 10 torpedoes and was armed with a 8.8 cm (3.46 in) deck gun.

UB-122 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).