The 1st U-boat flotilla also known as the Weddigen flotilla, was the first operational U-boat unit in Nazi Germany's Kriegsmarine (navy). Founded on 27 September 1935 under the command of Fregattenkapitän Karl Dönitz, it was named in honor of Kapitänleutnant Otto Weddigen. Weddigen, a U-boat commander during World War I, died on 18 March 1915 after his submarine U-29 was rammed by the British battleship HMS Dreadnought in the North Sea.
The 2nd U-boat Flotilla, also known as the Saltzwedel Flotilla, was the second operational U-boat unit in Nazi Germany's Kriegsmarine. Founded on 1 September 1936 under the command of Fregattenkapitän Werner Scheer, it was named in honour of Oberleutnant zur See Reinhold Saltzwedel. Saltzwedel, a U-boat commander during World War I, died on 2 December 1917, when his submarine UB-81 was sunk by a mine in the English Channel.
The 3rd U-boat Flotilla, also known as Lohs Flotilla, was the third operational U-boat unit in Nazi Germany's Kriegsmarine. Founded on 4 October 1937 under the command of Kapitänleutnant Hans Eckermann, it was named in honour of Oberleutnant zur See Johannes Lohs. Lohs, a U-boat commander during World War I, died on 14 August 1918 after his submarine UB-57 was sunk by a mine.
29th U-boat Flotilla was formed in December 1941 in La Spezia in Italy under the command of Korvettenkapitän Franz Becker. The flotilla operated mostly various marks of the Type VII U-boat and it concentrated its efforts mainly in the Mediterranean Sea, against convoys. In August 1943, the flotilla moved to Toulon, but did also have U-boats in Marseille and Salamis. The flotilla was disbanded in September 1944, when U-407 was sunk on September 19 and the two last flotilla boats U-565 and U-596 were scuttled in Salamis.
The 4th U-boat Flotilla was formed in May 1941 in Stettin under the command of Kapitänleutnant Werner Jacobsen. Nearly 300 boats received their basic training at the flotilla. The flotilla was disbanded in May 1945.
The 5th U-boat Flotilla, also known as Emsmann Flotilla, was a U-boat flotilla of Nazi Germany's Kriegsmarine during World War II.
The 8th U-boat Flotilla was formed in June 1941 in Königsberg under the command of Kapitänleutnant Georg-Wilhelm Schulz, who also at this time commanded the 6th U-boat Flotilla in Danzig. It was primarily a training flotilla but in the last months of the war some flotilla boats were in combat against the Soviet Navy in the Baltic Sea. The flotilla was disbanded in January 1945.
22nd U-boat Flotilla was formed in January 1941 in Gotenhafen under the command of Korvettenkapitän Wilhelm Ambrosius. The flotilla was disbanded in May 1945.
The 12th U-boat Flotilla was a German U-boat flotilla formed on 15 October 1942 at Bordeaux under the command of Korvettenkapitän Klaus Scholtz. The flotilla was disbanded on 25 August 1944 due to the imminent arrival of Allied forces.
21st U-boat Flotilla was a unit of Nazi Germany's Kriegsmarine before and during World War II. It was formed in 1935 as a Schulverband based at Kiel under the command of Kapitän zur See Kurt Slevogt.
The 18th U-boat Flotilla was a short-lived unit of Nazi Germany's Kriegsmarine during World War II.
The 19th U-boat Flotilla was a unit of Nazi Germany's Kriegsmarine during World War II.
20th U-boat Flotilla was a training flotilla of Nazi Germany's Kriegsmarine during World War II.
23rd U-boat Flotilla was a unit of Nazi Germany's Kriegsmarine during World War II.
24th U-boat Flotilla was a training flotilla ("Ausbildungsflottille") of Nazi Germany's Kriegsmarine during World War II.
26th U-boat Flotilla was a training flotilla of Nazi Germany's Kriegsmarine during World War II.
31st U-boat Flotilla was a training flotilla ("Ausbildungsflottille") of Nazi Germany's Kriegsmarine during World War II.
32nd U-boat Flotilla was a training flotilla ("Ausbildungsflottille") of Nazi Germany's Kriegsmarine during World War II.
27th U-boat Flotilla was a training flotilla ("Ausbildungsflottille") of Nazi Germany's Kriegsmarine during World War II.
33rd U-boat Flotilla was a front-line unit of Nazi Germany's Kriegsmarine during World War II.
Nazi Germany 
Kriegsmarine 
