Diving Spot of the Day: Cocos Island, Costa Rica — The Shark Supermarket of the Pacific
Cocos Island is a remote Costa Rican UNESCO World Heritage island 550 km offshore where hammerhead sharks school in the hundreds, whale sharks cruise the cleaning stations, and the Pacific's megafauna gathers in concentrations seen almost nowhere else.
The Island Jacques Cousteau Called the Most Beautiful in the World
Isla del Coco — Cocos Island — sits 550 kilometers southwest of the Costa Rican mainland in the eastern Pacific, so far offshore that it is accessible only by liveaboard, with a crossing time of 36 hours from Puntarenas. Jacques Cousteau reportedly called it the most beautiful island in the world. Whether or not that's accurate, its underwater environment is beyond dispute among divers who have made the journey: it is one of the handful of places on Earth where the open-ocean megafauna of the Pacific — hammerhead sharks, whale sharks, Galapagos sharks, silky sharks, manta rays, bottlenose dolphins, and sea turtles — gather in concentrations that seem improbable even when you're in the water with them.
The island itself is a national park and UNESCO World Heritage Site, part of the Eastern Tropical Pacific Marine Corridor shared with the Galapagos, Malpelo, and Coiba. No one lives on Cocos permanently; a small Costa Rican park ranger station is the only human presence. The island receives roughly 3,500–4,000mm of rain per year, making it one of the wettest places on Earth, and the resulting runoff feeds an extraordinary density of nutrients into the surrounding sea.
The Diving
There are approximately 20 named dive sites around the island, but the most famous concentrate around the seamounts and cleaning stations on the north and east sides. Dirty Rock (Roca Sucia) is the single most celebrated site — a pair of underwater pinnacles where scalloped hammerheads aggregate in schools that can reach several hundred individuals during peak season. The sharks come to be cleaned by barberfish and king angelfish, and they hover in the current with remarkable tolerance for careful, non-disruptive divers.
Alcyone, Manuelita, and Punta Maria round out the must-dive list. Whale shark encounters are common; the site consistently ranks among the top locations worldwide for reliable whale shark sightings, particularly from June through September. Manta rays, silky and Galapagos sharks, and large schools of jacks are present throughout the year.
Getting There from Korea
Flights: From Incheon (ICN), fly to San José Juan Santamaría International Airport (SJO) with a connection in Los Angeles (LAX) or Houston (IAH). Korean Air and American Airlines operate this route, with total travel time around 20–24 hours. From San José, ground transport or a domestic flight connects to Puntarenas port, where liveaboards depart for the 36-hour crossing.
Liveaboards and Practicalities
Cocos Island is accessible only by liveaboard — there are no land accommodations and no day trip boats. Operators include Undersea Hunter, Okeanos Aggressor, and Sea Hunter, all running 8–10 day itineraries that include 3–4 days of diving at the island. Typical per-person cost runs $4,500–7,000 USD depending on the vessel and season.
Best season: June–September for whale sharks; December–March for hammerhead aggregations; the site is good year-round. Water temperature: 22–28°C, thermoclines can drop to 18°C at depth — a 5mm or 7mm full suit is recommended.