Safety · Destination Guide
Cocos Island
Remote Pacific liveaboard diving where hammerheads gather around volcanic pinnacles
Safety · Destination Guide
Remote Pacific liveaboard diving where hammerheads gather around volcanic pinnacles
Cocos is isolated, environmentally sensitive, and often challenging in-water. Review the current 2026 park regulation, boat-specific dive rules, oxygen and search procedures, and mandatory dive-specific insurance. Site allocation, currents, weather, certified group leaders and emergency response govern what can safely happen. Conservation restrictions are enforceable park conditions, not optional etiquette.
Undersea Hunter reports currents and visibility can change within hours; its routine recreational rule is a maximum 30 m, no planned decompression, a buddy system, a dive computer and supervised skiff diving. Its FAQ describes supplied Nautilus diver locators and emergency oxygen on the skiffs, but confirm the actual departure's equipment. Aggressor requires certification proof, a computer, SMB/reel and dive-accident insurance. The 2026 park rules require scuba/apnea groups of 2 to 13 including guide, with scuba divemaster supervision and approved daytime sites only, normally 06:00-17:00. There is no routine night diving. Never rely on wildlife advertisements to evaluate personal ability. Provide the operator recent diving history and relevant medical information.
An offshore liveaboard is not near an emergency department or operational recompression chamber. Sea Hunter describes about 36 hours to San Jose by surface transport and park-ranger first-aid/paramedic support at Wafer Bay; other operator literature names mainland hyperbaric facilities but does not verify immediate access or transport. Do not assert an available helicopter or rapid evacuation. Confirm crew oxygen, satellite/radio, emergency contact process, medical equipment, search plan, insurance coverage for diving and remote evacuation, and how DAN/local responders will coordinate. In a life-threatening incident alert vessel crew and activate local rescue via the captain, then involve DAN at +1-919-684-9111; 911 is Costa Rica's land-based emergency number but may not connect directly offshore.
Remote evacuation and chamber access
The crossing is roughly 32-36 hours one way and vessel medical care is limited. Verify oxygen, rescue procedures, communications, insurance and evacuation planning before boarding.
Rapidly changing currents, swell and visibility
Surfacing away from the skiff, surge around pinnacles or poor visibility can turn a demanding dive unsafe. Respect surface signaling and the captain's go/no-go decision.
No regular night dives
The 2026 park regulation allows scuba and apnea immersions to start at 06:00 and finish before 17:00. Older promotional accounts of night dives are not current itinerary authority.
Wet trails and limited swimming access
Approved trail visits still require an escorted group, closed footwear and park sign-off. Swimming is restricted to specified beaches or pools and may be closed.
Decree 45744 replaced Decree 37023 in May 2026. Park entry and activity permits are compulsory; immersion sites, snorkeling zones, anchoring, trail routes and activities are controlled by ACMC. Prohibitions include fishing, marine wildlife touching/feeding/harassment, approaching megafauna feeding aggregations too closely by boat, scuba or snorkel, camping, unapproved landings, drones without the proper authorization and dumping waste. The current regulation specifically prohibits scuba/snorkeling in baitballs and approaching such feeding aggregations by vessel within 100 m. Avoid damaging reef and do not disturb cleaning-station animals. Protect the island's endemic rainforest and marine systems documented by UNESCO.
Do Not Do This
Avoid entering when remote evacuation and chamber access. Confirm local briefings before committing.
| Contact | Role | Phone | Availability |
|---|---|---|---|
| Liveaboard captain and dive director | Primary offshore emergency activation, radio coordination, oxygen and search/evacuation procedures | Use the vessel emergency contact sheet issued at boarding | Onboard during the booked expedition |
| Divers Alert Network medical emergency hotline | 24-hour dive emergency medical advice and coordination after alerting local responders | +1-919-684-9111 | 24/7, 365 days per year |
| Costa Rica emergency services | Police, ambulance and fire services on the mainland | 911 | 24/7 where phone connectivity exists; vessel communications required offshore |
| Aggressor after-hours travel emergency | Guest travel-delays line for Aggressor Adventure customers, not a substitute for vessel emergency procedures | +1-706-664-0111 | After hours only, per June 2026 operator travel document |
| Undersea Hunter Costa Rica office | Sea Hunter reservations and mainland voyage coordination, not 24-hour medical dispatch | +506-2228-6613 | Office availability to reconfirm before travel |