Okeanos Aggressor II — a dive-first yacht for Cocos Island

Cocos Island is the reason to choose this boat. The Okeanos Aggressor II is built around reaching one of the world's most demanding and rewarding pelagic destinations, then making repeated dives possible without giving up a private cabin, hot shower or proper meal. The route runs year-round, with 9-day/8-night and 11-day/10-night departures from Puntarenas to Puntarenas. Divers come looking for large animals rather than a catalogue of easy reef dives: schools of hammerheads, whitetip reef sharks, manta rays, tuna and the possibility of whale sharks. The boat suits divers who want that commitment packaged in a stable, comfortable liveaboard rather than a stripped-down expedition vessel.

The Okeanos Aggressor II makes the impression of a purpose-built dive yacht rather than a boat that happens to carry scuba gear. A spacious salon, shaded cocktail area and open sun deck give the group several places to spread out after a crossing or a demanding dive. Personal equipment lockers keep the dive kit out of the living areas, while the bar and grill shift the centre of the day outdoors when conditions allow. Inside, the layout is straightforward: move between cabin, salon and dive spaces without treating the yacht like a floating resort. The boat is diesel-powered and carries the equipment, storage and working areas needed for a remote Cocos itinerary. It feels organised around the water.

The atmosphere depends less on formal luxury than on a crew that keeps a remote trip running cleanly. The crew speaks English, and passengers consistently point to the cooking, the dive guides and the willingness to help as the reasons the boat stays in memory. That matters on a week spent in a confined space: meals arrive properly, dive questions get answered, and small preferences do not have to become problems. The crew also helps create a connection with Costa Rica; passengers describe the Costa Rican members of the team as genuinely hospitable. Evenings can hold fish-identification presentations, films, games or another dive-related discussion. The social centre is not forced. It grows around the day's sightings and the table.

Every dive starts with a full briefing from the dive staff. Dives are organised as buddy-team dives, with teams of two or three; a staff member is not counted as a buddy unless that staff member is diving alone with one guest. On dives from the yacht, staff may be in the water to offer support, help with photography or video, and point out smaller life, without directly supervising every team. Where tender diving is used, a staff member may accompany a tender group and help keep it together. The crew speaks English. Onboard training can include Advanced Open Water, Enriched Air Nitrox and other specialty courses such as navigation, buoyancy, fish identification and underwater naturalist training. Oxygen, first-aid kits and trained first-aid crew are carried on board, alongside radio, satellite communication and emergency equipment.

The dive operation uses 80 cu ft tanks, and the tanks accept both K-valves and DIN connections. Larger 100 cu ft or 15-litre tanks can be requested as a paid extra, subject to availability. Nitrox is available as a paid option, with 32% fills for certified nitrox divers; a nitrox course can also be taken on board. The shaded dive area has personal equipment storage, weight belts and weights, bacs de rinçage and a platform for water entries. Cameras get their own rinse tank and charging area. Sidemount is accepted only with a single cylinder, and rebreathers are not supported. Rental equipment and extra dives are optional extras. Divers should bring their own mask, fins, snorkel, BCD, regulator, pressure gauge and computer, along with exposure protection and surface-signalling equipment suited to the destination.

Between dives, the shaded dive area is the practical refuge, while the sun deck offers chaise lounges and deck chairs for those who want heat and open air. The salon is air-conditioned, with audio and video entertainment for crossings or weather-bound hours. Photographers have a dedicated camera room, charging stations and a separate camera rinse tank, so housings and batteries do not have to compete with wet dive gear. A bar, an outdoor grill and a dedicated photo space give the quiet hours a shape without pretending they are the main event. On a Cocos trip, the best use of the gap is often recovery: dry off, eat, check the camera, and be ready when the next briefing begins.

A day follows the needs of the diving rather than a hotel timetable. A briefing comes before each descent, then the dive, recovery on the platform or tender, food and the next tank change. The gaps are used for eating, drying equipment, checking cameras and resting in the shaded dive area or on the sun deck. The salon remains available for fish-identification presentations, films and other evening activities. On suitable itineraries, the day can finish with a night dive before dinner and sleep. The important rhythm is repetition: brief, dive, surface, eat, recover, then do it again. That is what makes the Okeanos Aggressor II a sensible platform for Cocos Island, where the value lies in being ready for the next encounter rather than rushing through one scheduled dive.

Food is one of the boat's strongest points. Meals combine Western and local cooking, with buffet and full-board service, non-alcoholic drinks, beer and wine with dinner. The galley serves the practical sequence a dive trip needs: substantial food between dives, snacks when the tanks are being filled, and a dinner that gives the day a proper finish. The chef is also used to adapting meals to dietary preferences, a detail that matters more on a remote itinerary than a decorative menu does. The table is part of the dive operation here. It puts energy back into divers before they return to the platform, then gives the group a place to compare the animals seen below.

The cabins are on the upper deck and in the middle of the boat, but they have no windows, so the cabin is a quiet, air-conditioned place to sleep rather than a lookout over the sea. Every cabin has a private bathroom and shower, with hot water available. Deluxe staterooms use a lower double bed with an upper twin bunk; the master stateroom has a queen bed, while the two suites offer twin beds or a king bed. The suites add more room and a more finished interior, including a picture window in the twin-bed suite. After a long crossing or a run of demanding dives, the useful luxury is simple: a cool room, a private shower and somewhere to close the door.

The cruise departs from and returns to Puntarenas, Costa Rica. A hotel transfer is included; an airport transfer is an optional extra. Divers are advised to arrive in Costa Rica at least the night before the cruise begins.