| Oceanbird | 53 | 2021 | Sanlorenzo |
| Oceane II | 28.6 | 1976 | CRN |
| Oceanic | 87.2 | 1969 | Schichau Unterweser AG |
| Oceanis | 28.6 | 1994 | Baglietto S.p.A. |
| Oceanos | 48.85 | 2006 | Mondomarine SpA |
| Oceans I | 29.87 | 2007 | Hargrave Custom Yachts |
| Oceans XI | 32.6 | 1991 | Hatteras Yachts |
| Oceanus V | 69.86 | 1968 | Aalborg Shipyard |
| Oceanus V | 48.77 | 2006 | Breaux Bay Craft |
| Oceanwolf | 38.1 | 1967 | Husumer Shipyard |
| Octave | 36.5 | 2017 | Sanlorenzo |
| Octavian | 33.2 | 1972 | Kröger Werft GmbH & Co |
| October | 38.4 | 2013 | Gulf Craft |
| Octopus | 126.2 | 2003 | Lürssen Yachts |
| Octopussy | 43.58 | 1988 | Heesen Yachts |
| Octopussy | 28.96 | 1998 | LeClercq Marine |
| Octopussy 7 | 32.2 | 2018 | Sanlorenzo |
| Oculus | 39.02 | 1996 | Oceanfast |
| Oculus | 37.11 | 2024 | Numarine |
| Odalisque | 35.36 | 1973 | Feadship |
| Odessa | 49.99 | 2007 | Turquoise Yachts |
| Odessa | 48.77 | 2009 | Christensen Shipyards, LLC. |
| Odessa II | 73.8 | 2013 | Nobiskrug |
| Odyssea | 46.7 | 2012 | Heesen Yachts |
| Odysseus | 29.7 | 1987 | CIM - Constructions Industrielles et Maritimes |
| Odyssey | 31.39 | 1999 | West Bay SonShip Yacht Builders Ltd. |
| Odyssey | 35.2 | 2016 | Sunseeker |
| Odyssey | 58.2 | 2013 | CRN |
| Odyssey III | 33 | 1967 | Benetti SpA |
| Odyssey London | 34 | 2008 | Custom Line |
| Ofelia | 34.4 | 2000 | Anadolu Shipyard (ADIK) |
| Off the Charts | 30.12 | 2014 | Princess Yachts |
| Official Plan | 33 | 2021 | Custom Line |
| Offline | 31.8 | 2021 | Overmarine Group SPA |
| Offline | 33.3 | 2024 | Overmarine Group SPA |
| Ohana | 49.7 | 2012 | Fitzroy Yachts |
| Okami | 29.7 | 2009 | Custom Line |
| Okeanis | 39.95 | 2003 | Ocea |
| Okko | 41.1 | 2013 | Mondomarine SpA |
| Oksanchik | 34.53 | 2013 | Sunseeker |
| Oktamar | 40 | 2014 | Liman JSC Shipbuilding Yard |
| Oktana | 38.5 | 1995 | Codecasa S.p.A. |
| Okto | 31.04 | 2012 | Azimut Yachts |
| Okto | 66.4 | 2014 | ISA Yachts |
| Ol'iva B | 30.69 | 2002 | Falcon Yachts S.r.l. |
| Olan | 31.68 | 2023 | Gulf Craft |
| Olde Salt | 34 | 2015 | Aegean Yacht |
| Olga | 34.44 | 1986 | Cantieri di Pisa |
| Oli | 35.5 | 2016 | Benetti SpA |
| Olivia | 37.54 | 2023 | Gulf Craft |
