O'Briens Cay Anchorage
Home to the famous Sea Aquarium snorkelling site — a wall dive in crystal-clear park waters.
O'Briens Cay lies just north of Cambridge Cay in the southern reaches of the Exuma Cays Land and Sea Park, best known for the Sea Aquarium — one of the most celebrated snorkelling sites in the Exumas. The protected waters west of the cay offer a single mooring and calm anchorage in settled conditions, positioning you perfectly for exploring the underwater world.
The Sea Aquarium features a wall descending to about 15 feet, carpeted with purple sea fans, sponges, and coral formations. Schools of yellowtail snapper, parrotfish, and grouper patrol the reef, emboldened by decades of no-take protection. A nearby plane wreck adds another dimension to the diving.
Approach and Anchoring
A single park service mooring west of O'Briens Cay can accommodate larger vessels up to 135 feet, available first-come, first-served. The anchorage offers good protection from easterly winds but is open from the northwest.
Most visitors reach the Sea Aquarium by dinghy from Cambridge Cay or Bell Island rather than overnighting at O'Briens itself. The clear, shallow waters make visual navigation straightforward, though coral heads require attention. Consult Explorer Charts for current conditions.
The Sea Aquarium
The Sea Aquarium snorkelling site occupies the northwest side of O'Briens Cay, where a coral wall descends to about 15 feet over sand. Mooring balls at the site allow you to tie off your dinghy while snorkelling.
The diversity of marine life here reflects the park's strict protections: schools of yellowtail snapper, angel fish, parrotfish, and various grouper species move fearlessly among the coral. Purple sea fans, orange sponges, and brain coral formations create an underwater garden.
Nearby Attractions
A short dinghy ride from the Sea Aquarium leads to the remains of a small plane wreck resting on the sandy bottom — an atmospheric dive site that complements the reef snorkelling.
O'Briens Cay itself offers no services or shore access within the protected park. Use this as a water-based destination, returning to Cambridge Cay or other moorings for overnight stays.
Getting there
O'Briens Cay sits between Cambridge Cay and Bell Island in the southern Exuma Cays Land and Sea Park. Most cruisers visit by dinghy from the Cambridge Cay mooring field or anchor briefly to access the Sea Aquarium. The cay is approximately 6 nautical miles north of Staniel Cay.
Frequently asked questions
- Is the Sea Aquarium good for beginner snorkellers?
- Yes. The site features calm, clear water with depths around 15 feet over sand. The wall provides interesting features without requiring advanced skills or freediving ability.
- Can I overnight at O'Briens Cay?
- The single mooring can accommodate overnight stays in settled conditions with easterly winds. However, most cruisers prefer the better-protected Cambridge Cay mooring field and visit the Sea Aquarium by dinghy.
- What makes the Sea Aquarium special?
- Decades of no-take protection mean the fish here are abundant and unafraid. The reef health, diversity, and fish behavior create an experience noticeably different from unprotected waters.
Nearby
Warderick Wells North Mooring Field
The crown jewel of the Exuma Cays Land and Sea Park — pristine waters, protected moorings, and the park headquarters.
ExploreEmerald Rock Mooring Field
A calm, current-free mooring field with easy beach access and miles of hiking trails at Warderick Wells.
ExploreWarderick Wells South Mooring Field
A secluded mooring field between Warderick Wells and Hog Cay with all-around wind protection.
Explore