• O cabalo, Bueu
• Oak Park
• Oak Park
• Oakland Ridge
• Oasis
• Oasis
• Oberoi House Reed
• Observatory
• Obyan
• Occhio di Dio
• Ocean Diver Wreck
• Octopus Reef
• Octubre Rojo
• Odyssey Wreck
• Oedolgae
• Office
• Ohinau
• Oil Rig Reef
• Ojo de Agua
• Okikawa Maru
• Okishima
• Oključna
• Okorotere Island
• Oksuz Ada
• Olang Sanctuary
• Old Aquarium
• Old Cement Barge
• Old Fort
• Old Isaacs
• Old Jetty
• Old Man's Hat
• Old Man's Hat
• Old Pian Island
• Old Quarry
• Old Wreck Head
• Oliveira e Carmo (Wreck)
• Olivetta
• Olowalu Beach
• Olympia Maru
• Olympia Regattastrecke
• Onderwater Natuurpark Zegersloot
• One Finger
• One Rock
• Oosterschelde, Bergse Diepsluis
• Oostvoornse Meer
• Oostvoornse Meer Slag Baardmannetje
• Open Ocean Habitat
• Opera House
• Orak Adası
• Orange Coral
• Orca Housereef
• Orchard Beach (A/k/a Captain Mike's Beach)
• Organ Loft
• Oriza Park Beach
• Orizaba
• Oro Verde (Bow)
• Oros
• Orud
• Osborn Shoals
• Osborne Shoals
• Osezaki
• Osprey
• Otomi Beach
• Otter Cove
• Ottoman Anchor
• Oued Yquem Wreck
• Outer Pinnacle
• Outer Rock
• Outhouse Beach
• Outpost
• Outside Crystal Cove
• Outside Edge, Aliwal Shoal
• Overhang 16-20Mts
• Overheat Reef
• Owens Reef
• Owhiro Bay
• Oyster Bridge
• Oyster Reef
• Oyster Stacks