Scuba Diving Cocos Island

The underwater world of the national park has become famous due to the attraction it holds for divers, who rate it as one of the best places in the world to view large pelagic species such as sharks, rays, tuna and dolphins.

Cocos Island National Park, located 550 km (375 miles) off the Pacific coast of Costa Rica, includes the entire Isla del Coco and the marine ecosystems up to a distance of 15 km around the island. Is the only island in the tropical Eastern Pacific with a tropical rainforest. Its position as the first point of contact with the northern equatorial counter-current, and the myriad interactions between the island and the surrounding marine ecosystem, make the area an ideal laboratory for the study of biological processes. The underwater world of the national park has become famous due to the attraction it holds for divers, who rate it as one of the best places in the world to view large pelagic species such as sharks, rays, tuna and dolphins.

Cocos Island National Park was designated a World Heritage Site by UNESCO in 1997.

The Isla del Coco is a large uprising of volcanic seamounts covered with untamed and uninhabited tropical rainforest featured in breathtaking scenes in the movie ‘Jurassic Park’. Cocos Island receives an average of 25 feet of rainfall per year, resulting in a covering of lush green foliage. Waterfalls abound, of which there are up to 70 falls of varying sizes during the peak of the rainy season. The island also supports verdant, high-altitude cloud forest. Rare for a small island, this is made possible by dramatic topography, abundant rainfall and surplus water stored in the porous reservoirs of the island itself. This extraordinary island ecosystem is unique to Cocos alone

The eco-system has been largely untouched by humans, offering us a rare glimpse into a world where nature reigns supreme, allowing the marine and island creatures to interact undisturbed and thrive in the process. The converging nutrient-rich currents from nearby deep water attract multitudes of pelagic action to Cocos.

The main attraction of Cocos Island diving is scalloped hammerhead sharks. Divers are treated to wave after wave of huge groups of hammerheads, some numbering in their hundreds! But there are other regular shark species encounters too, most notably whitetip reef sharks and Galapagos, silky, tiger, blacktip, silvertip and guitar sharks. They are joined by many different species of rays: mobula, marble, manta and eagle rays swirling around you in search of cleaning stations.

Besides the pelagic species – marlin, sailfish, rays and sharks – that are drawn to the area, you’ll find more than 25 endemic fish species, including the red-lipped batfish. Whales also use the Cocos Island seamount as a place to congregate and calve.


GETTING THERE: Because reaching Cocos Island National Marine Park requires a lengthy boat trip, most divers visit on a liveaboard dive vessel.

DIVE SEASON: The island is situated near the Equator where 2 weather patterns converge, which results in changeable weather, relatively cool equatorial air temperatures averaging 25.5°C, and average annual precipitation of over 7m. Rainfall alternates with sunny skies all year round. This however, does not affect the scuba action.

Dry Season – If you prefer calmer seas and higher visibility then book your trip between December and May.  The dry season typically sees calmer seas and visibility of over 30m.

Rainy Season – In fact, for many, the best time to dive at Cocos Island is in the ‘rainy’ season from June to December, when the nutrient upswells attract multitudes of hammerhead sharks, as well as manta rays and whale sharks. The surface is rougher during this period and The long open ocean crossing is likely to be less comfortable during rainy season.

WATER TEMPERATURE:  between 24-30°C (average 27.8°C) .  there is a seasonal variation of only a degree or two. However, temperatures can vary dramatically, dropping up to 6°C due to thermoclines

VISIBILITY:  Dry Season /Dec-May  12 – 30m  or 36- 90ft. Rainy Season/June-Dec visibility drops to within the range of 10 to 25m or 30-75ft.  Plankton rather than rainfall is more likely to be the factor that reduces visibility.

SPECIAL CONSIDERATION: Mandatory Surface Marker. There are moderate to strong currents.

SKILL LEVEL: Advanced, Experienced


There are approximately 20 dive sites that are situated relatively close together. The sites vary from  from shallow but steep vertical walls, drift diving, to deep pinnacles down to over 40m, and blue water dives.

Here are a few of the highlight sites

Bajo Alcyone– is the number one Costa Rica diving spot to see hundreds of hammerhead sharks and large fish action. Descending to the submerged mountain will give you the best seat in the house to see manta and mobula rays swirling into the cleaning stations and legions of hammerhead sharks on all sides of you as they descend to below the thermocline.

Dirty Rock – Made up of volcanic boulders and rock pinnacles rising just above the waves and separated by a sheltered 100m channel, this site is the most popular spot for diving at Cocos Island due to the sheer volume of hammerhead sharks and the incredible bio-mass of fish that congregate here. 

Dos Amigos Grande – This site, being the larger of the ‘Two Friends’, is dominated by a magnificent arch in its southwest corner. Descend to 25m where you can marvel as the arch rises from a depth of 28m to 19m below the ocean’s surface. The swim through is so large your whole dive group can fit through comfortably.

Dos Amigos Pequeña – Dropping into the strong surge on the west side and descending down onto the barren volcanic slopes at this remote spot, you can be forgiven for thinking that this site will not deserve a mention among the elite of the Cocos Island sites. However, think again. 

Everest – An undoubted highlight of your Costa Rica trip, or indeed your entire diving career, could be a truly unforgettable deep dive in a submersible craft. If there is availability and you have chosen to treat yourself then prepare for an unforgettable experience viewing the marine world through a large bubble at depths beyond which you have ever dived. 

Manuelita Deep – Manuelita Island is a 150m long islet, lying to the north of Chatham Bay, off the northeast corner of Cocos Island. The deeper west side is one of the prime spots to dive with hammerhead sharks. 

Manuelita Garden – Manuelita Island is a submerged mountain forming an islet to the north of Cocos Island, just out of Chatham Bay. The coral garden, otherwise known as Manuelita Inside, is located on the protected east side of the island and is likely to be the first site welcoming you to Cocos. 

Punta Maria – is an underwater mountain lying 500m off the southwest coast of Cocos Island. It is a made up of a large crown at 25m surrounded by deeper sloping walls, and a couple of pinnacles rising to 20m to the north. Punta Maria can only be visited when the current permits. It has a cleaning station for hammerheads as well as galapagos sharks.


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