Cocos Island is a remote, uninhabited Costa Rican national park and UNESCO World Heritage Site roughly 550 km off the Pacific coast, reachable only by a ~36-hour liveaboard crossing. It is one of the world's premier big-animal dive destinations, famous for daytime schools of scalloped hammerhead sharks numbering in the hundreds at its current-swept seamounts.
Destination info
Conditions, highlights, and the resident marine life.
Conditions
Water and air temperature across the year.
WaterAirDryShoulderWet
Description
Cocos Island (Isla del Coco) lies in the Eastern Tropical Pacific about 550 km southwest of mainland Costa Rica, halfway toward the Galápagos. Inscribed as a UNESCO World Heritage Site in 1997 and extended in 2002, it is the only oceanic island in the Eastern Tropical Pacific to carry a humid tropical rainforest; the 2,400-hectare island sits within a vast protected marine zone that Costa Rica expanded in December 2021 to roughly 54,844 km², ringed by the still-larger Bicentennial Marine Management Area. Diving is liveaboard-only — boats depart Puntarenas for a crossing of around 36 hours — and is reserved for advanced divers, with strong currents, surge, and pronounced thermoclines that can drop water temperature sharply on a single dive. The draw is pelagic abundance: exposed seamounts such as Bajo Alcyone host daytime aggregations of scalloped hammerheads (Sphyrna lewini) that gather at cleaning stations by the hundreds, alongside whitetip reef, Galápagos, silky, silvertip, and tiger sharks, marble and mobula rays, yellowfin tuna, dolphins, and — during the nutrient-rich wet season — whale sharks. Water sits around 24–30°C with thermoclines that can plunge several degrees, so a 5–7 mm full wetsuit is standard. The wet season (June–November) brings the strongest currents, plankton upwellings, and the biggest shark schools; the dry season (December–May) trades some of that action for calmer seas and clearer water.
Highlights
What makes this dive worth the trip.
Cocos Island National Park covers 202,100 hectares some 530 km off the Costa Rican mainland and is the only island in the Eastern Tropical Pacific with a humid tropical forest; UNESCO calls it among the most important sites in the region for protecting large pelagic migratory species such as the endangered scalloped hammerhead shark and the silky and Galápagos sharks.
Scalloped hammerheads (Sphyrna lewini) gather at Cocos by the hundreds during daylight at the seamounts to be cleaned and to socialise rather than hunt; a peer-reviewed acoustic-tagging study found residency was significantly greater at Alcyone — a shallow seamount about 3.6 km offshore — than at other sites, with presence concentrated in daytime hours.
On 22 April 2022, Costa Rica formally declared Cocos Island National Park a natural shark sanctuary (Executive Decree No. 43477-MINAE), protecting the 15 shark species that use the park; this followed the December 2021 expansion that enlarged the marine protected zone to roughly 54,844 km² and created the surrounding Bicentennial Marine Management Area.
Marine life
39 species you’re likely to encounter on a dive here.
Dive sites
6 signature sites at this destination.
Bajo Alcyone
Cocos Island's signature dive: an exposed seamount roughly 3.6 km off the southeast side of the island whose summit sits around 25–30 m, dropping deeper into the blue. Divers descend a fixed shot line into strong current and hold position near the rock to watch daytime schools of scalloped hammerheads — sometimes hundreds at a time — passing over cleaning stations, alongside large schools of bigeye jacks, yellowfin tuna, silky sharks, whitetip reef sharks, and marble rays, with mobula rays and the occasional whale shark in the blue. The premier hammerhead site in the park and one of the world's best.
25–40 madvancedLiveaboardVery strongVisibility 12–30 m
Dirty Rock
One of the most popular and dynamic sites at Cocos, a cluster of pinnacles off the northwest side of the island named for the guano-streaked rocks above water. Depths run from around 6 m down to roughly 30–40 m, with an average working depth near 30 m. Cleaning stations here draw schooling scalloped hammerheads in numbers, plus whitetip and blacktip reef sharks, Galápagos sharks, marble and eagle rays, mobula rays, bigeye jacks, tuna, green and hawksbill turtles, and visiting bottlenose dolphins and whale sharks.
6–40 madvancedLiveaboardStrongVisibility 12–30 m
Manuelita (Coral Garden & Deep)
Manuelita is a small islet off the northeast corner of Cocos within Chatham Bay, offering two distinct dives. The shallow, gently sloping south side — the Coral Garden — is Cocos Island's most famous night dive, where dozens of whitetip reef sharks hunt en masse across the reef after dark, and by day it serves as an easier orientation dive over coral with marble rays, turtles, and reef fish. The steeper north wall (Manuelita Deep / Outside) drops toward deep water with cleaning stations frequented by hammerheads, marble rays, and, on occasion, tiger sharks, with current that can build into a washing-machine effect at the north end.
5–35 mintermediateLiveaboardModerateVisibility 12–30 m
Dos Amigos Grande
The larger of two pinnacle islets a few hundred metres apart off the west to southwest side of Cocos. Divers make a rapid descent to around 25–30 m, and the site's signature feature is a huge underwater arch large enough for an entire dive group to swim through at once, often framed by schooling fish. A reliable spot for scalloped hammerheads, whitetip reef sharks, eagle and marble rays, yellowfin tuna, snappers and jacks, with tiger sharks and the occasional whale shark also recorded.
10–30 madvancedLiveaboardStrongVisibility 12–30 m
Punta Maria
A seamount off the southwest of the island whose ridge rises toward a peak, with a steep drop-off on one side; depths typically run from around 18–20 m down past 30 m. Reached by shot line, it is a noted Galápagos shark hotspot — large 3–3.5 m individuals patrol here — alongside scalloped hammerheads, silky sharks, whitetip reef sharks, eagle rays, manta and mobula rays, and barberfish cleaning stations. Its exposed position makes it a current-dependent dive best attempted by experienced groups.
18–40 madvancedLiveaboardStrongVisibility 12–30 m
Silverado
A shallow site, generally no deeper than about 13 m, built around a small pinnacle rising a couple of metres off a sandy slope — and the best place at Cocos to encounter silvertip sharks, which visit the pinnacle as a cleaning station. The shallow depth allows long bottom time and relaxed observation of the silvertips circling, with reef fish, jacks, and other sharks passing through. A good complement to the deep, high-current seamount dives.
5–18 mintermediateLiveaboardModerateVisibility 12–30 m
Where to dive & stay
Local dive centers, resorts, and hotels.
Featured operators coming soon
Verified dive centers, resorts, and hotels around Cocos Island will list here — pricing, photos, and direct contact.
