Sea Hunter — a working dive vessel built for Cocos

The Sea Hunter is for divers who choose Cocos Island for the animals, not for a short crossing or a polished resort at sea. The boat was built as a commercial dive-support vessel, and that purpose still shapes the trip: large skiffs, serious filling capacity, dedicated dive storage and a crew used to working far from shore. The reward is access to the sites that make Cocos worth the long voyage from Puntarenas—hammerheads moving through the blue, sharks at cleaning stations, rays, tuna and the occasional whale shark or manta. The vessel adds the comforts that matter after several days in current: private bathrooms, air-conditioning, hot showers, laundry service and food that has earned the strongest score of the trip. This is not the newest-looking liveaboard in the fleet. Its working-boat character shows, and some feedback points to the need for more cosmetic care. In return, the crew and diving operation are the parts passengers remember.

The Sea Hunter arrives with the blunt, capable look of a vessel that spent its earlier life supporting commercial divers. Its welded-steel hull and teak work deck are practical rather than decorative, while the inside has been finished as a liveaboard with an air-conditioned lounge, study and broad sundeck. The boat was built in 1994, but it is regularly taken apart for maintenance, repainted and serviced before the season. That distinction matters: the vessel is not presented as a pristine new yacht, and its boat score sits below the ratings for crew, food and diving. What guests gain is a platform designed around remote diving, with the space and equipment to move divers away from the mothership and bring them back efficiently. Once aboard, the working areas and the passenger spaces feel like two parts of the same machine.

The Sea Hunter’s strongest feature is the way the crew holds a remote expedition together. Dive masters brief clearly, skiff pilots track divers carefully, engineers keep the vessel functioning and the service team keeps cabins, meals and drinks moving without making passengers ask twice. The atmosphere is professional without becoming stiff. People tend to talk about the food, the skiff rides and the guides in the same breath because the parts connect: a good dive is followed by a hot rinse, fruit or pastries, a meal and a boat that is ready for the next descent. Evenings are more social than programmed, with conversation, audio-visual entertainment and the occasional celebration organised by the crew. The vessel itself has aged, but the people compensate in the places that matter most—safety, organisation, kindness and attention during a long week offshore.

Each dive group is led by two divemasters, with the group size commonly working out at roughly nine or ten divers. English and Spanish are spoken aboard. Briefings use a whiteboard: the guide draws the site, explains the entry and exit plan, identifies the current and points out what the group is likely to look for. The same divemaster who gives the briefing leads the dive. The buddy system is compulsory, dive time is limited to 60 minutes, decompression dives are not permitted and the maximum depth is 30 metres. This is a remote expedition, not a place for casual diving outside recreational limits. The skiffs carry oxygen, first-aid equipment, spare gear and VHF radios, while the mothership also carries emergency oxygen. Head counts are methodical, and the Nautilus Lifeline sends an activated diver’s position to the vessel and nearby VHF radios. Nitrox certification and other diver training can be arranged on board.

The dive system is built around two 24-foot heavy-duty fiberglass skiffs, plus a 17-foot rigid-bottom inflatable. The large skiffs carry up to ten divers with two divemasters and a pilot, use integrated tank racks and a solid fixed ladder, and provide shelter with a T-roof. Your gear stays on the skiff during the active diving days, so tanks do not have to be carried back and forth to the mothership; they are refilled in place within minutes after each dive. The boat carries 30 aluminium 80-cubic-foot tanks, two high-pressure compressors and a nitrox generator, with a large high-pressure storage bank. Nitrox is included, and the system also supports full oxygen service, technical diving and rebreathers; rebreather divers bring their own units. DIN adapters are available. Rental ScubaPro equipment includes BCDs, regulators, wetsuits, masks, fins, snorkels and nitrox computers. Camera storage, separate rinse tanks, shaded work areas and charging stations cover the needs of photographers. Each diver also receives a surface marker buoy, whistle, safety light and Nautilus GPS Lifeline.

Between dives, the Sea Hunter gives passengers a choice rather than a single crowded waiting area. The air-conditioned indoor lounge and study suit those who need shade, a quiet place or time with a camera, while the sundeck and terrace provide open air between skiff runs. Photographers have individual gear lockers, camera and strobe storage with 110- and 220-volt power, and separate camera-rinse tanks. The skiffs also have dedicated camera storage and T-roofs for shelter from sun and rain. When conditions and the diving plan allow it, the expedition leaves the water for Cocos itself: excursions include Chatham Bay, Wafer Bay and forest walks. Those landings are not a substitute for the diving, but they show the island that divers cannot see from a skiff.

A usual diving day begins with a briefing before the first morning descent. The general plan places one dive at 8 AM, a second at 11 AM and a third after lunch, around 2.30 PM, although the crew changes the order when current, weather or animal activity makes another choice safer or more productive. Breakfast comes before the first skiff run; the meal after the second dive restores energy, and snacks appear between water time and the afternoon descent. The skiffs remain the working base for the day, with tanks refilled there while divers eat, rest or prepare cameras. An afternoon island excursion may replace a dive for part of the group when conditions and the plan allow it. After the final return, there is time for a hot shower, dinner and the quiet work of drying gear before the boat continues the expedition or settles for the night.

The galley serves three meals a day, with snacks between dives and food available in buffet form. The cooking is Western in style and includes vegetarian and vegan options, with dietary requirements handled carefully by the kitchen team. Reviews consistently place the food among the Sea Hunter’s strongest points: plentiful, varied and prepared with more care than the basic liveaboard routine demands. Breakfast comes before the morning dives, the next meal follows the second dive, and the main meal after the afternoon dive gives the day its proper pause. Fresh fruit, pastries and other snacks appear when divers need them rather than only at formal mealtimes. Alcoholic and non-alcoholic drinks are included; beer and wine are available, while wine at dinner is optional. The table matters here because Cocos can make every dive physically demanding.

The cabins are arranged on the upper and lower decks, all with private bathrooms, air-conditioning, hot-water showers and 110-volt outlets. Lower-deck rooms come as twin cabins with two separate beds or double cabins with a queen bed and, where configured that way, an upper twin berth. The two upper-deck suites have desks, chairs, storage shelves and drawers, large windows and granite-finished bathrooms. Lower cabins use circular portholes and include hanging lockers, hooks, shelves and drawers for dive clothing and equipment. Daily housekeeping and complimentary laundry keep the practical side of a long expedition under control. The upper rooms bring more daylight; the lower rooms keep the arrangement simpler. Passenger reports describe the cabins as clean and, on at least one expedition, surprisingly quiet—useful after repeated dives and a long crossing.

Cocos Island expeditions depart from and return to Puntarenas, Costa Rica. Local transfers are listed separately from the liveaboard arrangements rather than included as part of the stay. Arriving in the area the night before departure is the sensible choice, leaving room for delays before boarding the Sea Hunter.