Cocos Island

June through November is a useful planning window for schooling scalloped hammerheads because wetter, more nutrient-rich ocean conditions can concentrate pelagic activity. This is a tendency, not a guarantee of sightings or a fixed daily season. The same period may bring rougher ocean crossings, stronger current and lower visibility than the relatively drier months. January through April can be more comfortable for transit and underwater visibility, yet sharks may still be seen. Always compare your dates with a liveaboard's permitted departures and its latest sea-condition report; weather and park site assignments override any season chart.

The practical visitor route is an authorized ocean-going liveaboard, not a day boat. Fly into Juan Santamaria International Airport (SJO), spend at least one night in San Jose and take the operator's scheduled ground transfer to Puntarenas. From the port, allow roughly 32 to 36 hours of Pacific crossing in each direction, depending on sea conditions. Sea Hunter, Okeanos Aggressor II and Cocos Island Aggressor are supported by 2026 operator evidence, although each sailing still needs confirmed park approval. A mainland hotel is not an island dive base; build time into your return travel for possible delays.

Cocos is not a good destination for a newly certified diver. Sea Hunter publishes Open Water as a nominal minimum, but explicitly discourages inexperienced divers and recommends deep-diving training and at least 25 hours of prior experience. Dives may approach 30 m under its recreational depth cap, with unpredictable current, variable visibility and exposed skiff recoveries. Other vessels set their own acceptance and supervision rules. Have the operator review your certification, logged dives, recent experience and comfort in strong current before booking. Being allowed aboard does not guarantee permission to enter every assigned site.

Costa Rica's 2026 Decree 45744 allows park-authorized snorkeling and apnea as separate activity categories. Article 16 identifies specific snorkeling locations in Wafer and Chatham Bays, with group and rescue-boat requirements; Article 17 covers apnea groups at authorized sites. This does not demonstrate that a dive-focused liveaboard sells a dedicated snorkel or freedive package, provides apnea safety specialists or accepts a non-diver. Ask the actual vessel for written confirmation of the activity permission, staff, equipment and any restrictions. Never treat open-ocean shark scuba sites as suitable for an unsupervised swim or breath-hold session.

A non-diver can potentially join an accepted liveaboard guest itinerary and request permitted shore activities, but should not expect a separate resort stay. The 2026 park regulation lists escorted walks between Chatham and Wafer Bays, waterfall routes and selected viewpoints. Visits require park authorization, a boat crew escort, guide coverage, closed footwear and an appropriate time window. Cerro Yglesias needs additional administrator approval; any trail may close for safety or conservation. Undersea Hunter describes usually one or two shore visits during a dive expedition. Confirm non-diver booking eligibility and how often the specific boat actually lands before paying.

Do not plan on recreational night dives. The May 2026 Decree 45744 states that scuba and apnea immersions may begin after 06:00 and must finish before 17:00, while Aggressor explicitly says that no night diving is currently offered at Cocos. Sea Hunter also enforces a recreational limit of 30 m and prohibits planned decompression on normal cruises. Some operator marketing mentions specialist rebreather capabilities, but this does not establish permission for recreational technical or overhead dives. Any specialist filming, rebreather or research expedition requires separate direct approval, safety arrangements and activity-specific conditions.

The vessel and its passengers need park-entry approval and permission for each proposed activity under Decree 45744, which replaced the older Decree 37023 in May 2026. The park posts statutory daily charges of USD $50 for nonresidents, USD $25 for Costa Rican nationals or residents, and USD $20 for recreational scuba rights. Operator invoices use their own multi-night park packages: Sea Hunter lists USD $554 for 10 nights, while Aggressor lists USD $490 plus 13% VAT. Additional evacuation, fuel and transfer charges depend on the vessel. Check the final quote and whether the operator has secured the definitive entry resolution.

Distance is the defining risk. The open-ocean crossing takes roughly 32 to 36 hours and there is no nearby tourist hospital or guaranteed rapid recompression service. Sea Hunter reports first-aid oxygen and diver locator procedures plus some park ranger paramedic capability; these do not substitute for a full medical evacuation plan. Reviewed operators require proof of dive-specific insurance, and Aggressor also lists a separate evacuation plan fee. Ask the captain about current search and rescue equipment, satellite communication, medical staff limits, evacuation arrangements and insurance acceptance. In an emergency notify the vessel first and use DAN's emergency hotline, +1-919-684-9111, for coordination.

Carry your physical or digital scuba certification, proof of dive-specific accident cover, mandatory dive computer, surface marker buoy, personal medications and a plan for seasickness. Undersea Hunter recommends a 5mm wetsuit for water often around 24°C to 29°C, with cooler thermoclines possible. Bring a dry bag, closed grippy shoes for any permitted shore trail, a rain layer, sun protection and a compatible charging adapter. Check which tanks, Nitrox, rentals and locator devices the exact vessel supplies. Pack lightly, preferably in soft luggage, and do not assume mainland shops or an ATM will exist after departure.

This is a premium, multi-thousand-dollar expedition rather than a low-cost shore-diving trip. Aggressor's published 2026 price table lists deluxe cabins on Cocos Island Aggressor at about USD $6,849 and Okeanos Aggressor II at about USD $6,399 for a 10-night itinerary, before possible promotions or extra charges. Budget separately for international flights, San Jose nights, dive insurance, park packages, any emergency evacuation plan, fuel surcharge, rentals, Nitrox and tips. Sea Hunter publishes its own terms and differing transfer charges. Rates and permitted sailing dates change, so obtain a specific itemized quote before making nonrefundable flight plans.

Alcyone, Dirty Rock, Manuelita Outside, Chatham Bay and Punta Maria regularly appear in dive-operator descriptions. Alcyone and Dirty Rock are strongly associated with hammerhead cleaning stations; Manuelita mixes wall and reef settings; Chatham Bay can serve as a checkout dive with smaller reef wildlife. These names are destinations of interest, not a guaranteed stop list. Decree 45744 requires designated and permitted activity areas, and the operator must follow park allocations, visibility, swell and diver ability. Do not book based on a named site being promised every day, and do not infer that an offshore scuba site is open to snorkeling or apnea.