The SM UB-129 was a German Type UB III submarine or U-boat in the German Imperial Navy during WWI. She was built by AG Weser of Bremen and following just under a year of construction, launched at Bremen on 11 May 1918. She was commissioned into the German Imperial Navy on 11 June 1918 as SM UB-129.
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.
Her engines enabled her to travel at 13.9 knots (25.7 km/h; 16.0 mph) when surfaced and 7.6 knots (14.1 km/h; 8.7 mph) when submerged.
She was lost 31 October 1918 in Fiume (Rijeka, Croatia) after the surrender of Austria-Hungary in WWI.
