The Great Blue Hole is a 300 m wide, 125 m deep submarine sinkhole at the centre of Lighthouse Reef Atoll, declared a UNESCO World Heritage Site and made famous by Jacques Cousteau. Divers descend through the hole's cobalt-blue water to 40 m to see perfectly preserved stalactites formed when the cavern was above sea level during the last ice age. Bull sharks, Caribbean reef sharks, and midnight parrotfish cruise the outer walls.
Aliwal Shoal is a fossilised sand dune reef 5 km off Umkomaas on the KwaZulu-Natal south coast, internationally renowned for its aggregations of ragged-tooth sharks (grey nurse) sheltering in the caves and gutters between June and November. Oceanic blacktip sharks, bottlenose dolphins, humpback whales (winter), and large potato bass make every dive eventful, while the shoal's twin peaks — Cathedral and the Pinnacles — offer dramatic topography at 5–32 m. Boat entry through the surf is standard.
Formigas (Ants) is a tiny, remote islet east of Santa Maria in the Azores surrounded by a broad rocky bank rising from 300 m to just 17 m below the surface. Between April and October the bank is reliably visited by whale sharks attracted by the summer plankton blooms, alongside large schools of amberjack, barracuda, and hammerheads. The Azorean sea temperature at 20–23°C and Atlantic clarity combine to make this one of Europe's finest open-ocean dive experiences.
Princess Alice Bank is a mid-Atlantic seamount rising from 2000 m to within 40 m of the surface near Faial in the Azores, considered one of the world's elite big-animal dive sites. Seasonal aggregations of blue sharks, mako sharks, hammerhead sharks, and huge schools of Atlantic amberjack gather above the summit, with blue marlin and whale shark encounters adding to the spectacle in summer. The site is current-swept and remote, demanding open-water confidence and liveaboard access.
Protea Banks is a remote offshore reef 9 km from Shelly Beach in KwaZulu-Natal and is widely considered one of the premier shark dives on the planet. In winter (June–November) large numbers of ragged-tooth sharks congregate on the southern pinnacle, while tiger sharks, bull sharks, oceanic blacktips, and seasonal hammerhead schools patrol the northern end. Strong ocean swells, significant current, and depths of 25–40 m restrict this site firmly to advanced, experienced divers.
Big Brother and Little Brother are two remote limestone pillars rising from the deep Red Sea, accessible only by liveaboard. Their sheer walls are plastered with pink and orange soft corals and attract oceanic species rarely seen in shallower sites, including thresher sharks, hammerheads, and silky sharks. The north plateau of Big Brother also hosts two impressive wreck dives — the Numidia and the Aida.
Tubbataha Reef is a UNESCO World Heritage Site in the middle of the Sulu Sea, reachable only by liveaboard from Puerto Princesa, Palawan. The north atoll wall drops precipitously from the surface to over 100 m and is patrolled by hammerhead sharks, grey reef sharks, and Napoleon wrasse in extraordinary numbers. Conditions demand experience — current, depth, and open-ocean exposure combine on many of the park's best sites.
The Elbow at the southern tip of Turneffe Atoll is famous as one of Belize's best current dives, where tidal flow funnels past the reef tip carrying a constant stream of horse-eye jacks, creole wrasse, and spotted eagle rays. Nurse sharks rest on sandy ledges at 20 m and great hammerheads are reliably sighted here in late winter. The drift is exhilarating on a strong tide and very manageable on neap tides.