Nestled in the heart of the Pacific Ocean, Cocos Island, Costa Rica, is a diver’s paradise—a remote, rugged sanctuary renowned for its unparalleled biodiversity and thrilling underwater encounters. This UNESCO World Heritage site is a magnet for adventurers seeking to explore some of the planet’s most pristine marine ecosystems.
Cocos Island offers a variety of dive sites, each promising a unique and exhilarating experience. The waters around the island are a veritable aquarium, home to a staggering array of marine life. Dive beneath the surface to explore dramatic volcanic rock formations, coral-covered pinnacles, and vast underwater mountains. The island's nutrient-rich currents attract large pelagic species, making every dive an adrenaline-filled encounter.
Diving in Cocos Island is a once-in-a-lifetime experience, offering an unrivaled blend of marine biodiversity, dramatic underwater landscapes, and thrilling big-animal encounters. Whether you’re an experienced diver chasing adrenaline or a nature lover seeking to immerse yourself in one of the world’s most vibrant ecosystems, Cocos Island promises to deliver an unforgettable underwater adventure.
Marine Life and Seasonal Encounters :
Hammerhead Sharks (Year-Round): One of the main draws of Cocos Island is the immense schools of scalloped hammerhead sharks. These majestic creatures are present year-round, but the best sightings are during the rainy season (June to November), especially in the month of August and September when they congregate in large numbers around cleaning stations.
Tiger Sharks (Year-Round): Adding to the thrill, tiger sharks patrol the waters of Cocos Island year-round. Known for their size and distinctive stripes, these apex predators are often spotted during dives, particularly at sites like Alcyone and Manuelita.
Whitetip Reef Sharks and Galápagos Sharks (Year-Round): Keep an eye out for whitetip reef sharks and Galápagos sharks, both commonly seen around the island. The swift currents and underwater topography provide perfect conditions for these agile hunters.
Dolphins, Turtles, and Reef Fish (Year-Round): Alongside the big pelagics, divers can enjoy sightings of playful dolphins, graceful turtles, and a kaleidoscope of tropical reef fish. The vibrant coral reefs are alive with color, home to everything from moray eels to parrotfish.
Whale Sharks (June to September): From June to September, the world’s largest fish graces the waters of Cocos Island. Encountering a whale shark is a bucket-list experience, as these gentle giants glide gracefully through the deep blue.
Manta Rays and Mobula Rays (December to May): The dry season (December to May) brings the arrival of manta rays and mobula rays, which can often be seen performing acrobatic displays in the open water. These graceful creatures are a sight to behold as they sweep through the currents with effortless elegance.
Best Time to Dive :
Cocos Island offers world-class diving year-round, but the experience varies with the seasons:
June to November (Rainy Season): Expect stronger currents, but also the highest concentration of hammerheads, whale sharks, and large schools of fish. This is the season for adrenaline-seekers looking for big action.
December to May (Dry Season): The seas are calmer, visibility improves, and encounters with manta rays and other pelagics increase. This season is perfect for divers who prefer more stable conditions but still want thrilling marine life encounters.
One of our crazy friends/divers who went Cocos for 9 times in different season told us he thinks August - September has the largest populations of hammerheads and big action. Although during Jun to Oct has slightly less visibility, is actually the best time of the season to dive. This is due to the nutrient upwells that it causes which attract unbelievable large schools of hammerheads, other sharks and large rays.
Top Dive Sites :
Alcyone : Depth: 27 - 36m
One of the most famous dive sites around Cocos Island, Alcyone is a submerged mountain located about 25 meters below the surface. Strong currents make this site a magnet for large schools of hammerhead sharks, as well as silky sharks, eagle rays, and the occasional whale shark. The adrenaline rush as you’re surrounded by hundreds of hammerheads is something every diver should experience.
Dirty Rock : Depth: 6 - 39m
A pinnacle rising from the depths, Dirty Rock is another hotspot for schooling hammerheads. The dive begins with a descent along the rock wall, where you’ll often spot Galápagos sharks, jacks, and sometimes even manta rays. Keep an eye on the blue for passing dolphins or, if you’re lucky, a tiger shark.
Manuelita Coral Garden : Depth: 6 - 21m
For those who enjoy a slightly more relaxed dive, Manuelita Coral Garden offers a vibrant reef teeming with smaller marine life. The shallow depths make it perfect for extended bottom times, and it’s common to see whitetip reef sharks, moray eels, and a variety of colorful reef fish. This site also offers night diving, where divers can witness the nocturnal activities of hunting whitetips.
Manuelita : Depth: 18 - 39m
Adjacent to the Coral Garden, Manuelita Outside is known for its encounters with tiger sharks and large schools of jacks. The site’s varied topography, including walls, ledges, and sandy flats, provides habitats for a wide range of marine species. The dive often concludes with a thrilling safety stop where rays and turtles are frequent visitors.
Bajo Alcyone : Depth: 30 - 35m
Located near the main Alcyone site, Bajo Alcyone is another submerged pinnacle famous for its hammerhead sightings. The currents here can be strong, bringing in large pelagics such as whale sharks, manta rays, and barracudas. Divers often witness the mesmerizing sight of hammerheads ascending from the depths in perfect formation.
Dos Amigos Grande & Dos Amigos Pequeño : Depth: 27 - 39m
These twin islets offer dramatic arches and tunnels carved through volcanic rock. The larger of the two, Dos Amigos Grande, features a massive archway where divers can swim through and encounter hammerheads, eagle rays, and sometimes even marlin. Dos Amigos Pequeño is known for its swim-throughs and vibrant coral gardens.
