
German submarine U-1 was the first U-boat built for Nazi Germany's Kriegsmarine following Adolf Hitler's abrogation of the terms of the Treaty of Versailles in 1935, which banned Germany possessing a submarine force.

SM U-5 or U-V was the lead boat of the U-5 class of submarines or U-boats built for and operated by the Austro-Hungarian Navy before and during the First World War. The submarine was built as part of a plan to evaluate foreign submarine designs, and was the first of three boats of the class built by Whitehead & Co. of Fiume after a design by Irishman John Philip Holland.

SM U-5 was a German Type U 5 U-boat built for the Imperial German Navy. She was commissioned 2 July 1910 in Germaniawerft in Kiel. She served in World War I under the command of Kptlt. Johannes Lemmer, with no recorded sinkings of enemy ships on two patrols. She was lost in an accident off the Belgian coast on 18 December 1914, and sank with no survivors - all of her 29 crew members lost their lives.

SM U-10 was one of the 329 submarines serving in the Imperial German Navy in World War I.

SM U-11 was one of the 329 submarines serving in the Imperial German Navy in World War I.

German submarine U-12 was a Type IIB U-boat of Nazi Germany's Kriegsmarine laid down on 20 May 1935 by Germaniawerft at Kiel and commissioned on 30 September.

SM U-12 or U-XII was a U-5-class submarine or U-boat built for and operated by the Austro-Hungarian Navy before and during the First World War.

German submarine U-22 was a Nazi German Type IIB U-boat which was commissioned in 1936 following construction at the Germaniawerft shipyards at Kiel. Her pre-war service was uneventful, as she trained crews and officers in the rapidly expanding U-boat arm of the Kriegsmarine following the abandonment of the terms of the Treaty of Versailles two years before.

German submarine U-25 was one of two Type IA ocean-going submarines produced by Nazi Germany's Kriegsmarine. Constructed by DeSchiMAG AG Weser in Bremen as yard number 903, U-25 was commissioned on 6 April 1936. It experienced a short, but successful combat career, sinking eight ships and damaging one.

German submarine U-40 was a Type IXA U-boat of Nazi Germany's Kriegsmarine that operated during World War II.

German submarine U-44 was a Type IXA U-boat of Nazi Germany's Kriegsmarine that operated during World War II. She was ordered in November 1936 and laid down in September 1938 in Bremen. She was launched in August 1939 and commissioned in November.

German submarine U-50 was a Type VIIB U-boat of Nazi Germany's Kriegsmarine during World War II. Ordered on 21 November 1936, she was laid down as yard number 585 at the yards of Friedrich Krupp Germaniawerft AG in Kiel on 3 November 1938. She was launched on 1 November 1939 and commissioned on 12 December 1939 by Kapitänleutnant (Kptlt.) Max-Hermann Bauer, who was the sole commander of the boat. In her short career she conducted only two patrols, both as part of the 7th U-boat Flotilla. In this time she succeeded in sinking four ships, totalling 16,089 gross register tons (GRT).

German submarine U-54 was a Type VIIB U-boat of Nazi Germany's Kriegsmarine during World War II.

SM U-74 was a Type UE 1 submarine and one of the 329 submarines serving in the Imperial German Navy in World War I. U-74 was engaged in the naval warfare and took part in the First Battle of the Atlantic.

SM U-106 was one of the 329 submarines serving in the Imperial German Navy in World War I. U-106 was commissioned on 28 July 1917, under the command of Kapitänleutnant Hans Hufnagel, and participated in one wartime patrol starting on 2 September 1917. On 18 September 1917, during the First Battle of the Atlantic, U-106 was credited with the sinking of HMS Contest, an Acasta class destroyer, and damaging "City of Lincoln", a 5,867 ton steamer, in the Western Approaches. She was lost off Terschelling after striking a mine on 7 October 1917.

German submarine U-171 was a Type IXC U-boat of Nazi Germany's Kriegsmarine built for service during World War II. It was laid down on 1 December 1940 at the DeSchiMAG AG Weser yard at Bremen as yard number 1011, launched on 22 July 1941, and commissioned on 25 October 1941 under the command of Kapitänleutnant Günther Pfeffer.

German submarine U-455 was a Type VIIC U-boat built for Nazi Germany's Kriegsmarine for service during World War II. She was laid down on 3 September 1940, launched on 21 June 1941 and commissioned on 21 August with Kapitänleutnant Hans-Henrich Giessler in command of a crew of 51.

German submarine U-1020 was a Type VIIC/41 U-boat of Nazi Germany's Kriegsmarine during World War II.

German submarine U-1273 was a Type VIIC/41 U-boat of Nazi Germany's Kriegsmarine during World War II.

German submarine U-2323 was a Type XXIII submarine of Nazi Germany's Kriegsmarine during World War II. She was constructed at Hamburg during the spring of 1944, completed on the 18 July and given to Kptlt. Walter Angermann to command. A fast high-technology coastal boat, U-2323 was expected to be the new war-winning weapon in the Kriegsmarine's arsenal.

German submarine U-2342 was a short-lived Type XXIII U-boat of Nazi Germany's Kriegsmarine during the Second World War. She was built at Hamburg during 1944 as a modern Type XXIII "Elektroboote", a small coastal class designed to strike ships along the coastlines of Britain and liberated Europe, particularly the English Channel, although none ever served there. U-2342 was placed under the command of Oblt.z.S.d.R. Berchtold Schad von Mittelbiberbach, a former senior non-commissioned officer, who received a field promotion in 1943. She was his first submarine experience.

SM UB-45 was a Type UB II submarine or U-boat built for and operated by the German Imperial Navy during World War I. UB-45 operated in the Mediterranean and the Black Seas, and was sunk by a mine in November 1916.

SM UB-46 was a Type UB II submarine or U-boat for the German Imperial Navy during World War I. UB-46 operated in the Mediterranean and the Black Seas, and was sunk by a mine in December 1916.

SM UB-53 was a German Type UB III submarine or U-boat in the Imperial German Navy during World War I. She was commissioned into the Pola Flotilla of the German Imperial Navy on 21 August 1917 as SM UB-53.

SM UB-55 was a German Type UB III submarine or U-boat in the German Imperial Navy during World War I. She was commissioned into the Flanders Flotilla of the German Imperial Navy on 1 July 1917 as SM UB-55.

SM UB-56 was a German Type UB III submarine or U-boat in the German Imperial Navy during World War I. She was commissioned into the Flanders Flotilla of the German Imperial Navy on 19 July 1917 as SM UB-56.

SM UB-57 was a German Type UB III submarine or U-boat in the German Imperial Navy during World War I. She was commissioned into the Flanders Flotilla of the German Imperial Navy on 30 July 1917 as SM UB-57.

SM UB-58 was a German Type UB III submarine or U-boat in the German Imperial Navy during World War I. She was commissioned into the Flanders Flotilla of the German Imperial Navy on 10 August 1917 as SM UB-58.

SM UB-61 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 23 June 1917 as SM UB-61.

SM UB-75 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 11 September 1917 as SM UB-75.

SM UB-81 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 18 September 1917 as SM UB-81.

SM UB-104 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 15 March 1918 as SM UB-104.

SM UB-109 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 31 December 1917 as SM UB-109.

SM UB-116 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 24 May 1918 as SM UB-116.

SM UB-123 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 6 April 1918 as SM UB-123.

SM UB-127 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 June 1918 as SM UB-127.
SM UC-42 was a German Type UC II minelaying submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 20 November 1915 and was launched on 21 September 1916. She was commissioned into the German Imperial Navy on 18 November 1916 as SM UC-42.

SM UC-57 was a German Type UC II minelaying submarine or U-boat in the German Imperial Navy during World War I. The U-boat was ordered on 12 January 1916, laid down on 14 March 1916, and was launched on 7 September 1916. She was commissioned into the German Imperial Navy on 22 January 1917 as SM UC-57. In seven patrols UC-57 was credited with sinking 5 ships, either by torpedo or by mines laid.