SM UB-33 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 22 July 1915 and launched on 5 December 1915. She was commissioned into the German Imperial Navy on 22 April 1916 as SM UB-33.
SM UB-19 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 30 April 1915 and launched on 2 September 1915. She was commissioned into the German Imperial Navy on 16 December 1915 as SM UB-19. The submarine sank 13 ships in 15 patrols for a total of 10,040 gross register tons (GRT). UB-19 was sunk in the English Channel at 49°56′N2°45′W on 30 November 1916 by British Q ship HMS Penshurst.
SM UB-20 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 30 April 1915 and launched on 26 September 1915. She was commissioned into the German Imperial Navy on 10 February 1916 as SM UB-20. The submarine sank 13 ships in 15 patrols for a total of 10,230 gross register tons (GRT). UB-20 was mined and sunk on 28 July 1917 at 51°21′N2°38′E. Fifteen crew members died in the event.
SM UB-21 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 30 April 1915 and launched on 26 September 1915. She was commissioned into the German Imperial Navy on 20 February 1916 as SM UB-21. The submarine sank 33 ships in 26 patrols for a total of 36,764 gross register tons (GRT). Surrendered to Britain in accordance with the requirements of the Armistice with Germany, UB-21 was sunk as a target by HMS Terror in the Solent on 30 September 1920; the wreck was sold in 1970 and most had been cleared by 1998, although some remnants survive.
SM UB-22 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 30 April 1915 and launched on 9 October 1915. She was commissioned into the German Imperial Navy on 2 March 1915 as SM UB-22. The submarine sank 27 ships in 18 patrols for a total of 16,645 gross register tons (GRT). UB-22 was mined and sunk in the same incident with the torpedoboat SMS S16 in the North Sea at 54°40′N6°32′E on 19 January 1918 in a British minefield.
SM UB-23 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 30 April 1915 and launched on 9 October 1915. She was commissioned into the Imperial German Navy on 13 March 1916 as SM UB-23. The submarine sank 51 ships in 21 patrols for a total of 33,880 gross register tons (GRT). On 26 July 1917, UB-23 was badly damaged by a depth charge attack by HMS PC-60 off the Lizard; she put in at Corunna, Spain, on 29 July 1917 and was interned. On 22 January 1919 she was surrendered to France in accordance with the requirements of the Armistice with Germany, and she was broken up in Cherbourg in July 1921.
SM UB-24 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 30 April 1915 and launched on 18 October 1915. She was commissioned into the German Imperial Navy on 18 November 1915 as SM UB-24. The submarine was surrendered to France in accordance with the requirements of the Armistice with Germany on 24 November 1918 and broken up in Cherbourg in July 1921.
SM UB-28 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 30 April 1915 and launched on 20 December 1915. She was commissioned into the German Imperial Navy on 27 December 1915 as SM UB-28.
SM UB-30 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 22 July 1915 and launched on 16 November 1915. She was commissioned into the German Imperial Navy on 18 March 1916 as SM UB-30.
SM UB-31 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 22 July 1915 and launched on 16 November 1915. She was commissioned into the German Imperial Navy on 25 March 1916 as SM UB-31.
SM UB-34 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 22 July 1915 and launched on 5 December 1915. She was commissioned into the German Imperial Navy on 10 June 1916 as SM UB-34.
SM UB-35 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 22 July 1915 and launched on 28 December 1915. She was commissioned into the German Imperial Navy on 22 June 1916 as SM UB-35.
SM UB-36 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 22 July 1915 and launched on 15 January 1916. She was commissioned into the German Imperial Navy on 22 May 1916 as SM UB-36.
SM UB-37 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 22 July 1915 and launched on 28 December 1915. She was commissioned into the German Imperial Navy on 17 June 1916 as SM UB-37.
SM UB-38 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I.
SM UB-39 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I.
SM UB-41 was a German Type UB II submarine or U-boat in the German Imperial Navy during World War I.
SM UB-62 was a German Type UB III submarine or U-boat in the German Imperial Navy during World War I. She was commissioned into the German Imperial Navy on 9 July 1917 as SM UB-62.
SM UB-90 was a German Type UB III submarine or U-boat in the German Imperial Navy during World War I. She was commissioned into the German Imperial Navy on 21 March 1918 as SM UB-90.
SM UB-108 was a German Type UB III submarine or U-boat in the German Imperial Navy during World War I. She was commissioned into the German Imperial Navy on 1 March 1918 as SM UB-108.
German Empire 
