|Ordered:||15 December 1937|
|Builder:||DeSchiMAG AG Weser, Bremen|
|Laid down:||5 March 1939|
|Launched:||20 December 1939|
|Commissioned:||30 March 1940|
|Status:||Missing since 22 June 1940|
|Class and type:||German Type IXB submarine|
|Draught:||4.70 m (15 ft 5 in)|
|Test depth:||230 m (750 ft)|
|Complement:||48 to 56 officers and ratings|
She was ordered on 15 December 1937 and was laid down on 5 March 1939 at DeSchiMAG AG Weser, Bremen, becoming yard number 954. She was launched on 20 December 1939 and commissioned under her first and only commander, Korvettenkapitän Hans-Günther Looff on 30 March 1940.
German Type IXB submarines were slightly larger than the original German Type IX submarines, later designated IXA. U-122 had a displacement of 1,051 tonnes (1,034 long tons) when at the surface and 1,178 tonnes (1,159 long tons) while submerged. The U-boat had a total length of 76.50 m (251 ft), a pressure hull length of 58.75 m (192 ft 9 in), a beam of 6.76 m (22 ft 2 in), a height of 9.60 m (31 ft 6 in), and a draught of 4.70 m (15 ft 5 in). The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of 4,400 metric horsepower (3,240 kW; 4,340 shp) for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of 1,000 metric horsepower (740 kW; 990 shp) for use while submerged. She had two shafts and two 1.92 m (6 ft) propellers. The boat was capable of operating at depths of up to 230 metres (750 ft).
The submarine had a maximum surface speed of 18.2 knots (33.7 km/h; 20.9 mph) and a maximum submerged speed of 7.3 knots (13.5 km/h; 8.4 mph). When submerged, the boat could operate for 64 nautical miles (119 km; 74 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 12,000 nautical miles (22,000 km; 14,000 mi) at 10 knots (19 km/h; 12 mph). U-122 was fitted with six 53.3 cm (21 in) torpedo tubes (four fitted at the bow and two at the stern), 22 torpedoes, one 10.5 cm (4.13 in) SK C/32 naval gun, 180 rounds, and a 3.7 cm (1.5 in) SK C/30 as well as a 2 cm (0.79 in) C/30 anti-aircraft gun. The boat had a complement of forty-eight.
She carried out two combat patrols with the 2nd U-boat Flotilla. On her first foray in May 1940, she transported an 88 mm Flak (anti-aircraft gun) with ammunition, some bombs, 90 cbm (some 750 barrels (119 m3)) of fuel for aircraft and some motor oil to Trondheim during the Norwegian campaign. On 23 May she encountered an enemy submarine in the North Atlantic, but neither boat attacked each other. She sank a single ship during her career, the SS Empire Conveyor (5911 BRT) on 20 June 1940.
She was declared missing with all hands after 22 June 1940 between the North Sea and the Bay of Biscay. She may have collided with the vessel San Felipe on 22 June, or been sunk by depth charges from the corvette HMS Arabis on 23 June.
Some Dutch and Polish authors suggest that U-122 was sunk after being rammed by the submarine ORP Wilk on 20 June soon after midnight. The first officer of Wilk reported in his memoiries ramming a surfaced U-boat while it was attempting to dive. This version was often disputed and an alternative theory states that Wilk instead rammed and sank the Dutch submarine O-13, or most probably, a minefield protector buoy rather then a submarine. Moreover, the U-122 sank the SS Empire Conveyor during the day following the Wilk's collision, and she was too far away then, and reported her position for the last time on 21 June.
- Kemp 1999, p. 66.
- Gröner 1991, p. 68.
- Helgason, Guðmundur. "The Type IXB boat U-122". German U-boats of WWII - uboat.net. Retrieved 3 October 2014.
- Andrzej S. Bartelski (in Polish). Tajemnica ataku ORP Wilk (A mystery of ORP Wilk attack). "Morze, Statki i Okręty" nr 11/2013 (139), p. 30-40
- "Dutch Submarines: The Wilk case part one". Retrieved 3 October 2014.
- Busch, Rainer; Röll, Hans-Joachim (1999). German U-boat commanders of World War II : a biographical dictionary. Translated by Brooks, Geoffrey. London, Annapolis, Md: Greenhill Books, Naval Institute Press. ISBN 1-55750-186-6.
- Busch, Rainer; Röll, Hans-Joachim (1999). Deutsche U-Boot-Verluste von September 1939 bis Mai 1945 [German U-boat losses from September 1939 to May 1945]. Der U-Boot-Krieg (in German). IV. Hamburg, Berlin, Bonn: Mittler. ISBN 3-8132-0514-2.
- Gröner, Erich; Jung, Dieter; Maass, Martin (1991). U-boats and Mine Warfare Vessels. German Warships 1815–1945. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.
- Kemp, Paul (1999). U-Boats Destroyed – German Submarine Losses in the World Wars. London: Arms & Armour. ISBN 1-85409-515-3.
- Helgason, Guðmundur. "The Type IXB boat U-122". German U-boats of WWII - uboat.net. Retrieved 29 December 2014.