| U-121 | Type IIB |
| Feldpost Number | M 01 240 |
| Construction Yard | Flender Werke AG, Lübeck-Siems |
| Yard Number | 269 |
| Ordered | 28th Sep 1937 |
| Keel laid | 16th Apr 1938 |
| Launched | 20th Apr 1940 |
| Commissioned | 28th May 1940 |
| Baubelehrung | Marinelehrwerkstatt, Kiel /
Baubelehrung U-Boote Ostsee, Kiel |
| Training, Flotillas and Duties |
| 05.40 - 06.40 | U Schule Flottille, Neustadt
Schulboot (training boat)
|
| 07.40 - 05.45 | 21.U-Flottille, Pillau
Schulboot (training boat)
|
| Commanders |
| 05.40 - 03.41 | OL Karl-Ernst Schroeter
see also: U-752 |
| 10.40 - 11.40 | OL Otto Harms
see also: U-6 U-56 U-464 |
| 11.40 - 11.40 | OL Adalbert Schnee
see also: U-6 U-60 U-201 U-2511 |
| 03.41 - 07.41 | OL Egon Reiner Frhr von Schlippenbach
see also: U-453 |
| 07.41 - 03.42 | KL Gert Hetschko
see also: U-453 |
| 03.42 - 04.42 | OL Ernst von Witzendorff
see also: U-46 U-101 U-650 U-267 U-2524 U-1007 |
| 05.42 - 02.43 | LT Otto Westphalen
see also: U-121 U-968 |
| 09.42 - 12.42 | LT Otto Hübschen
see also: U-7 U-60 U-145 U-2501 U-2542 |
| 02.43 - 02.44 | OL Ewald Hülsenbeck
see also: U-146 U-121 U-1209 |
| 02.44 - 05.45 | OL Friedrich Horst |
ubootwaffe.net