| Name | Build year | Nationality | Bilde | Loss during WW2 |
|---|---|---|---|---|
| D/T O.K.Hauge | 1921 | Norway | ||
| Okonomi | Unknown | Norway | ||
| Oko år ukjent | Unknown | Norway | ||
| D/S Oksfjord | 1891 | Norway | ||
| D/S Oksvald | 1927 | Norway | Requisitioned/confiscated by Axis power, 1941-5-? | |
| D/S Oksø | 1873 | Norway | ||
| D/S Oksø | 1899 | Norway | ||
| M/S Oksøy | 1962 | Norway | ||
| M/S Oksøy | 1994 | Norway | ||
| Jernbark Okta | 1874 | Norway | ||
| M/T Oktan | 1953 | Norway | ||
| Oktav | Unknown | Norway | ||
| D/S Olaf | 1907 | Norway | ||
| M/S Olaf | 1919 | Norway | ||
| Skonnert Olaf | 1858 | Norway | ||
| D/S Olaf Bergh | 1921 | Norway | ||
| M/S Olaf Fostenes | 1936 | Norway | Torpedoed, 1942-9-18 | |
| M/S Olaf Gustav | 1891 | Norway | ||
| M/S Olaf (H 91 A ) | Unknown | Norway | ||
| Bark Olaf Kyrre | 1866 | Norway | ||
| D/S Olaf Kyrre | 1886 | Norway | ||
| D/S Olaf Kyrre | 1867 | Norway | ||
| D/S Olaf Kyrre | 1895 | Norway | ||
| M/S Olaf Scheel | 1964 | Norway | ||
| D/S Olaf Trygvesøn | 1876 | Norway |