| U-6 | Type IIA |
| Feldpost Number | M 00 130 |
| Construction Yard | Deutsche Werke AG, Kiel-Gaarden |
| Yard Number | 241 |
| Ordered | 2nd Feb 1935 |
| Keel laid | 11th Feb 1935 |
| Launched | 21st Aug 1935 |
| Commissioned | 7th Sep 1935 |
| Baubelehrung | Marinelehr-und Reparaturwerkstatt, Kiel |
| Training, Flotillas and Duties |
| 09.35 - 06.40 | U-Schule Flottille, Neustadt Schulboot (training boat) Frontboot (operational)
|
| 07.40 - 08.44 | 21.U-Flottille, Pillau Schulboot (training boat)
|
| Commanders |
| 07.09.35 - 30.09.37 | OL ~ KL Ludwig Mathes see also: U-9 U-44 |
| 01.10.37 - 17.12.38 | OL Werner Heidel see also: U-7 U-55 |
| 17.12.38 - 26.11.39 | OL ~ KL Joachim Matz see also: U-59 U-70 |
| 11.39 - 12.39 | OL Hans-Bernhard Michalowski see also: U-62 |
| 27.11.39 - 17.01.40 | OL Otto Harms see also: U-56 U-121 U-464 |
| 18.01.40 - 16.06.40 | OL Otto Adalbert Schnee see also: U-60 U-121 U-201 U-2511 |
| 06.40 - 07.40 | KL Georg Peters see also: U-8 U-11 U-A U-38 |
| 11.07.40 - 03.41 | OL Johannes Liebe see also: U-48 U-332 |
| 03.41 - 09.41 | OL Eberhard Bopst see also: U-597 |
| 10.41 - 08.42 | OL Herbert Brüninghaus see also: U-148 U-1059 |
| 08.42 - 09.42 | OL Paul Just see also: U-151 U-546 |
| 09.42 - 19.10.42 | OL Herbert Brüninghaus see also: U-148 U-1059 |
| 20.10.42 - 06.43 | LT ~ OL Otto Niethmann see also: U-476 U-3507 |
| 06.43 - 08.43 | LT Alois König |
| 08.43 - 10.43 | LT Horst Heitz see also: U-792 U-1407 |
| 10.43 - 16.04.44 | OL Alois König |
| 17.04.44 - 09.07.44 | LT Erwin Jestel see also: U-1204 |