She was commissioned into the German Imperial Navy on 11 June 1918 as SM UB-129.

[Note 1] UB-129 was lost 31 October 1918 in Fiume (45°19′N 14°26′E / 45.317°N 14.433°E / 45.317; 14.433) after the surrender of Austria-Hungary.

UB-129 was commissioned later the same year under the command of Kptlt.

Like all Type UB III submarines, UB-129 carried 10 torpedoes and was armed with a 10.5 cm (4.13 in) deck gun.

UB-129 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).