Ships hit by U-31
See the profile page for U-31
| Date | U-boat | Commander | Name of ship | Tons | Nat. | Convoy | ||
| 16 Sep, 1939 | U-31 | Johannes Habekost | Aviemore | 4.060 |  | br | OB-4 | |
| 24 Sep, 1939 | U-31 | Johannes Habekost |  | Hazelside | 4.646 | | br | |
| 1 Dec, 1939 | U-31 | Johannes Habekost | | Arcturus | 1.277 |  | nw | |
| 3 Dec, 1939 | U-31 | Johannes Habekost | Ove Toft | 2.135 |  | da | ||
| 4 Dec, 1939 | U-31 | Johannes Habekost | Gimle | 1.271 | | nw | ||
| 4 Dec, 1939 | U-31 | Johannes Habekost | | HMS Nelson (28) (d.) [Mine] | 33.950 | | br | |
| 4 Dec, 1939 | U-31 | Johannes Habekost | Primula | 1.024 | | nw | ||
| 6 Dec, 1939 | U-31 | Johannes Habekost | Agu | 1.575 |  | es | ||
| 6 Dec, 1939 | U-31 | Johannes Habekost | Vinga | 1.974 |  | sw | ||
| 23 Dec, 1939 | U-31 | Johannes Habekost | HMS Glen Albyn [Mine] | 82 | | br | ||
| 23 Dec, 1939 | U-31 | Johannes Habekost | HMS Promotive [Mine] | 78 | | br | ||
| 22 Sep, 1940 | U-31 | Wilfried Prellberg | | Union Jack | 81 |  | fa | |
| 27 Sep, 1940 | U-31 | Wilfried Prellberg | Vestvard | 4.319 | | nw | OB-218 | |
| 29 Oct, 1940 | U-31 | Wilfried Prellberg | Matina | 5.389 | | br | ||
| 61.861 | ||||||||
| 13 ships sunk (27.911 tons) and 1 ship damaged (33.950 tons).
[Mine] indicates the vessel was hit by a mine laid by said U-boat.
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