| Ship Name | Hull No. | IMO No. | ENI No. | Year Built | Date Taken | Location |
|---|---|---|---|---|---|---|
| FS Orion | M645 | 1986 | 2008-08-09 | Toulon | ||
| Orion | 8865640 | 1991 | 1998-05-27 | River Elbe | ||
| fv Orion | BF432 | 9222156 | 2000 | 2012-04-09 | Mallaig | |
| pv Orion | 2010 | 2012-06-25 | Rotterdam | |||
| Orion Leader | 9182289 | 1999 | 2003-09-27 | Southampton | ||
| Orka - Veerhaven X | 2007 | 2012-06-25 | Rotterdam | |||
| Orko | 9430325 | 2008 | 2024-07-15 | Solent | ||
| Orla | 9154270 | 1999 | 2001-09-01 | River Thames | ||
| Orla | 9154270 | 1999 | 2003-05-03 | River Thames | ||
| Orlando | 7431258 | 1976 | 1997-04-18 | Dunkerque | ||
| Orlik | 1948 | 2012-04-15 | Macduff | |||
| RMAS Oronsay | A284 | 9201607 | 2000 | 2000-10-12 | Portsmouth Harbour | |
| HMS Orpheus | S11 | 1960 | 1988-03-12 | Portsmouth Harbour | ||
| Orsett | 1966 | 2000-06-17 | Hull | |||
| Ortac | 1974 | 1998-01-21 | Southampton | |||
| Ortac | 1974 | 1999-08-15 | Southampton | |||
| Ortrud | 1978 | 1999-01-20 | Southampton | |||
| Ortviken | 9087374 | 1996 | 2001-09-01 | River Thames | ||
| Ortviken | 9087374 | 1996 | 2003-05-03 | River Thames | ||
| Ortviken | 9087374 | 1996 | 2003-08-16 | River Thames | ||
| Ortviken | 9087374 | 1996 | 2010-06-20 | Rotterdam | ||
| Ortviken | 9087374 | 1996 | 2010-06-20 | Rotterdam | ||
| Ortviken | 9087374 | 1996 | 2012-06-24 | Rotterdam | ||
| TCG Oruçreis | F245 | 1996 | 2005-07-03 | Portsmouth Harbour | ||
| HMS Orwell | M2011 | 1985 | 1996-07-21 | Portsmouth Harbour | ||
| HMS Orwell | M2011 | 1985 | 1998-02-04 | Portsmouth Harbour | ||
| Osaka Express | 2007 | 2012-06-26 | Rotterdam | |||
| Oscar | 1975 | 2021-07-16 | Firth of Clyde | |||
| Osceola | 1943 | 1994-09-20 | Norfolk, Virginia | |||
| Osco Stripe | 1990 | 1995-08-24 | Hamburg | |||
| RNLB Osier | 17-34 | 2002 | 2008-05-06 | River Tyne | ||
| Osios David | 7639068 | 1977 | 2002-06-21 | Vlissingen | ||
| HMS Osiris | S13 | 1964 | 1988-03-12 | Portsmouth Harbour | ||
| HMS Osiris | S13 | 1964 | 1988-07-29 | Portsmouth Harbour | ||
| HMS Osiris | S13 | 1964 | 1989-07-23 | Portland Harbour | ||
| HMS Osiris | S13 | 1964 | 1989-10-07 | Portsmouth Harbour | ||
| Oski | 1979 | 1988-11-06 | San Francisco | |||
| Oslo Trader | 9509700 | 2011 | 2013-06-22 | River Mersey | ||
| Osprey | 1991 | 2007-03-25 | Kielder Water | |||
| fv Osprey | BA4 | 9021710 | 1991 | 2017-09-02 | Kirkcudbright | |
| fv Osprey | WK14 | 1965 | 2012-04-12 | Scrabster | ||
| Osprey Boxer | 9577989 | 2010 | 2010-08-08 | River Tyne | ||
| Osprey Boxer | 9577989 | 2010 | 2010-08-10 | River Tyne | ||
| Osprey Carrier | 2008 | 2010-08-10 | River Tyne | |||
| Osprey Carrier | 2008 | 2014-04-20 | Firth of Forth | |||
| Osprey Fighter | 9438937 | 2007 | 2010-08-08 | River Tyne | ||
| Osprey Fighter | 9438937 | 2007 | 2010-08-10 | River Tyne | ||
| Osprey Fighter | 9438937 | 2007 | 2012-09-16 | Aberdeen | ||
| Ostara | 1961 | 2012-06-23 | Rotterdam | |||
| Ostara | 8303185 | 1983 | 1997-04-20 | Rotterdam | ||
| Ostend Way | 7816501 | 1980 | 2008-05-17 | River Thames | ||
| Oster | 5266386 | 1908 | 2005-05-12 | Bergen | ||
| Osterems | 9148207 | 1999 | 2009-09-27 | Blyth | ||
| Osterhook | 8412003 | 1985 | 2002-06-21 | Vlissingen | ||
| pv Osteriff | 1997-06-05 | River Elbe | ||||
| Ostrand | 9087362 | 1996 | 1998-05-16 | River Thames | ||
| Ostrand | 9087362 | 1996 | 2002-08-31 | River Thames | ||
| Ostsee | 9105152 | 1995 | 1995-08-21 | River Elbe | ||
| Ostsee | 9105152 | 1995 | 2006-05-06 | River Medway | ||
| Ostsee | 9105152 | 1995 | 2011-06-28 | Rotterdam | ||
| Otapan | 6508561 | 1965 | 2002-06-16 | Amsterdam | ||
| Otello | 8919934 | 1992 | 2002-04-20 | Southampton | ||
| Ottawa Express | 9165360 | 1998 | 2014-05-31 | River Mersey | ||
| HMS Otter | S15 | 1962 | 1989-03-27 | Portsmouth Harbour | ||
| Otter - Veerhaven 13 | 1964 | 2010-06-21 | Rotterdam | |||
| Otterbank | 9126376 | 1996 | 2016-05-22 | Firth of Clyde | ||
| Otto | 1973 | 2011-06-26 | Rotterdam | |||
| Otto Höch | 1949 | 1998-05-27 | Hamburg | |||
| HMS Otus | S18 | 1963 | 1989-04-16 | Portsmouth Harbour | ||
| Oualidia | 7711878 | 1978 | 1997-10-17 | Southampton | ||
| Oualidia | 7711878 | 1978 | 1998-07-04 | Southampton | ||
| Ouarsenis | 7420209 | 1976 | 2002-06-21 | Vlissingen | ||
| Ouarzazate | 7422178 | 1975 | 1989-04-16 | Portsmouth Harbour | ||
| Oued Eddahab | 9143843 | 1998 | 2002-01-27 | Southampton | ||
| Oued Ziz | 9143855 | 1998 | 2001-03-20 | Hamburg | ||
| Ouessant | 6807345 | 1968 | 1989-08-20 | Bordeaux | ||
| FS Ouessant | S623 | 1978 | 1989-07-05 | Portsmouth Harbour | ||
| Ouirgane | 7422180 | 1975 | 1998-01-21 | Southampton | ||
| Ouirgane | 7422180 | 1975 | 2002-06-22 | Dunkerque | ||
| Oulmes | 7711866 | 1978 | 1989-05-20 | Portsmouth Harbour | ||
| Oulmes | 7711866 | 1978 | 1999-09-14 | Southampton | ||
| fv Our Catherine | BRD77 | 1989 | 2024-05-10 | Tarbert, Loch Fyne | ||
| Our Fantasia | 1953 | 2010-07-31 | River Mersey | |||
| fv Our Frances | BH39 | 1971 | 2012-08-26 | River Tyne | ||
| fv Our Heritage | FR237 | 1976 | 2013-12-07 | Kirkcudbright | ||
| fv Our Heritage | MT127 | 1976 | 2015-03-08 | Whitehaven | ||
| fv Our Heritage | MT127 | 1976 | 2024-09-12 | Peterhead | ||
| Our Lady Pamela | 8508931 | 1986 | 1988-02-07 | Portsmouth Harbour | ||
| Our Lady Pamela | 8508931 | 1986 | 1988-02-14 | Portsmouth Harbour | ||
| Our Lady Pamela | 8508931 | 1986 | 1989-06-11 | Portsmouth Harbour | ||
| Our Lady Pamela | 8508931 | 1986 | 1998-02-18 | Portsmouth Harbour | ||
| Our Lady Pamela | 8508931 | 1986 | 2002-07-06 | Portsmouth Harbour | ||
| Our Lady Pamela | 8508931 | 1986 | 2003-09-27 | Portsmouth Harbour | ||
| Our Lady Pamela | 8508931 | 1986 | 2009-06-13 | Portsmouth Harbour | ||
| Our Lady Patricia | 8507494 | 1986 | 1988-02-25 | Portsmouth Harbour | ||
| Our Lady Patricia | 8507494 | 1986 | 1989-07-02 | Portsmouth Harbour | ||
| Our Lady Patricia | 8507494 | 1986 | 1989-10-07 | Portsmouth Harbour | ||
| Our Lady Patricia | 8507494 | 1986 | 2000-06-08 | Portsmouth Harbour | ||
| Our Lady Patricia | 8507494 | 1986 | 2001-08-24 | Portsmouth Harbour | ||
| Our Lady Patricia | 8507494 | 1986 | 2002-09-02 | Portsmouth Harbour |