Isla del Coco National Park, Costa Rica
Cocos Island
Uninhabited island 550km off the Pacific coast of Costa Rica, reachable only by a 36-hour liveaboard crossing, dived almost exclusively for schooling scalloped hammerheads at seamount cleaning stations.
- Scalloped hammerhead
- Tiger shark
- Sharks
- Strong current
Best season
Best Jun–Oct
Minimum cert
Advanced + experience
Water
25–28°C
Current
strong
Season
When this place works
Liveaboards run year-round; there is no closed season. The seasonal split is a quality trade rather than an access one: Jun-Oct rainy season gives the best hammerhead schooling and the worst visibility (9-20m), Dec-May dry season gives up…
Why dive here
What this place is known for
01sharkSchooling scalloped hammerheads
The reason the trip exists. Cleaning stations at Alcyone, Dirty Rock and Manuelita hold schools that can run to hundreds of animals overhead. You hold position behind rock in current and wait rather than swim at them.
Seasonality — shouldershouldershouldershouldershoulderpeakpeakpeakpeakpeakshouldershoulder
02sharkMulti-species shark diversity
Beyond the hammerheads: whitetip reef sharks in numbers that support a well-known night feeding behaviour at Manuelita, plus Galapagos, silky, blacktip and tiger sharks.
03pelagicRays and large schooling fish
Under-advertised relative to the hammerheads. Marbled rays in aggregations, eagle rays, mantas, plus dense schools of jacks and giant trevally. Several divers report the marbled ray fields as the more memorable dive.
Marine life
Twelve-month species timelines
Present year-round; schooling behaviour peaks in the Jun-Oct rainy season, which is also when visibility is at its worst. That trade-off is the central booking decision for Cocos and most operators…
Very high densities. The Manuelita night dive, where dozens hunt cooperatively across the reef, is a signature Cocos dive and does not depend on season.
Reported alongside the rainy-season hammerhead peak. Occasional rather than expected.
Regular at Manuelita Channel in recent years. Unbaited, unlike Tiger Beach.
Conditions
What the water is like
Water temp
25–28°C
15°C — 32°C
Visibility
9–30 m
0 m — 40 m
Current
strong
mild — strong
Thermoclines
Expected
likely
Minimum certification — Advanced + experience
Strong current and significant surge are the norm, not the exception. Operators expect solid buoyancy and the ability to deploy an SMB independently, because blue-water ascents away from the pinnacle are routine. Deep sites past 30m.…
Entries — boat
Recommended & required
- nitrox — recommended. Recommended by operators; repeated deep dives over consecutive days.
Logistics
How people dive it
10-12 days
scuba
The only access. 36 hours each way from Puntarenas, so a 10-day trip yields roughly 7 dive days. No land facilities, no shore access, no…
Operators
Who to book with
Loading operators…
Sources & verification
Check the evidence.
Every destination is independently researched and major claims link back to their sources.
Know this place?
Spot something outdated, have local knowledge, or think something is missing?
Submissions are reviewed and verified before the dataset is updated.