| Name | Build year | Nationality | Bilde | Loss during WW2 |
|---|---|---|---|---|
| D/S Northland | 1911 | USA | ||
| D/S O. B. Martin | 1944 | USA | ||
| O. L. Bodenhamer | 1944 | USA | ||
| D/T Olney | 1920 | USA | ||
| D/S Oneida | 1919 | USA | Ran aground, 1943-5-4 | |
| D/S Orbis | 1899 | USA | ||
| D/S Oregonian | 1917 | USA | Torpedoed, 1942-9-13 | |
| T/T Oregon Trail | 1943 | USA | ||
| D/S Orland Loomis | 1943 | USA | ||
| D/T Oscar F. Barrett | 1943 | USA | ||
| D/T Oscar S. Straus | 1943 | USA | ||
| D/S Ozark | 1919 | USA | ||
| T/S Panama | 1939 | USA | ||
| D/S Panaman | 1913 | USA | ||
| D/S Pan Kraft | 1919 | USA | ||
| D/T Pan-Maine | 1936 | USA | ||
| D/S Pan-York | 1901 | USA | ||
| D/T Papoose | 1921 | USA | Torpedoed, 1942-3-19 | |
| D/S Parismina | 1908 | USA | Torpedoed, 1942-11-18 | |
| T/T Patrick. J. Hurley | 1941 | USA | Torpedoed, 1942-9-13 | |
| D/S Paul Hamilton | 1942 | USA | Attacked from air, 1944-4-20 | |
| D/S Paul Hamilton Hayne | 1942 | USA | ||
| T/T Paulus Hook | 1944 | USA | ||
| D/S Pennsylvania | 1920 | USA | ||
| D/S Pere Marquette | 1943 | USA |