Okeanos Aggressor II Liveaboard Overview

diver in silhouette swimming underwater with fins and a gaugeDIVEIN contributor Rebecca Strauss taking a selfie near a city canal
By
Emily Cook
A wearer of many hats, Emily is happiest when her hair flows free underwater. During her PDIC certification dive in Maine, a lobster tried to fight...
Rebecca Strauss
DIVEIN contributor Rebecca Strauss taking a selfie near a city canal
Editor at DIVEIN.com
Rebecca has been an avid traveler and scuba diver for many years. She began her editorial career by updating travel guides, which took her all over...
Okeanos Aggressor II liveaboard dive boat cruising past a lush green coastline
At 120 feet (36 m), the Okeanos Aggressor II accommodates 22 passengers within 11 staterooms.
Aerial view of the Okeanos Aggressor II anchored off a reef near Cocos Island
The real treasure for scuba divers lies 36 hours offshore at Cocos Island, uninhabited save for several national park rangers on rotating shifts.
School of hammerhead sharks swimming in the blue waters off Cocos Island
During the rainy season (May through November), divers are more likely to see hundreds of hammerhead sharks.
School of butterflyfish swimming together over a reef at Cocos Island
There's lots of fish life along with the sharks in Cocos.
Dolphins swimming through a large school of jacks near Cocos Island
You never know what you'll see underwater in Cocos.
Hammerhead shark cruising past a reef with yellow snapper at Cocos Island
Hammerheads are present on many dives.
Panoramic view of a forested island and reef near Cocos Island
This stunning island was allegedly the inspiration behind Treasure Island and Jurassic Park.
Dining room set with wine and place settings on the Okeanos Aggressor II
Fuel up pre- or post-dive in the spacious dining room.
Chef holding a fruit platter carved into an owl shape aboard the Okeanos Aggressor II
Staff put in extra effort to create fun, artistic edible decorations that are sure to impress and delight you.
Diver swimming beside a large school of jacks off Cocos Island
Schooling fish are present on most Cocos dives.
Hammerhead shark swimming close to camera with reef fish nearby at Cocos Island
Hammerheads are nearly guaranteed in Cocos.

Costa Rica conjures up images of tropical forests and cerulean waters, but the real treasure for scuba divers lies 36 hours offshore at Cocos Island, uninhabited save for several national park rangers on rotating shifts. Allegedly the inspiration behind Treasure Island and Jurassic Park, Cocos may not be home to any dinosaurs, but the population and diversity of sharks here is sure to give you thrills.

Diving in Costa Rica from the Okeanos Aggressor II immerses you in an unspoiled underwater world. As a bonus, the Okeanos Aggressor II is part of The Green Fleet, committed to sustainability to help protect the area. The vessel was built in 1985 with stability in mind for crossings to Cocos Island. Renovations in 2010 modernized the boat and enhanced comfort for passengers. Photographers will especially enjoy the large camera table on the dive deck. Everyone will appreciate the hammock and lounge areas while cruising to Cocos Island.

Dive in to discover more about the Okeanos Aggressor II and Cocos Island.

About this overview

To help you decide whether this liveaboard fits your dive style, budget, and comfort needs, we’ve researched the boat, itinerary, onboard experience, diving setup, and overall value.
We review liveaboards based on the details that matter most during a multi-day dive trip, including cabins, food, crew support, dive operations, safety, route quality, and how the boat compares with similar options in the destination.

Recommended in: Liveaboards in Costa Rica

Things we like:

  • Secluded location with abundant marine life
  • Hammock on the sun deck
  • Unlimited beer and wine included

Things we don't like:

  • High price tag for amenities included
  • 36-hour journey to/from Cocos can be choppy
  • Visibility under 80 feet (24 m) during rainy season

Diving on the Okeanos Aggressor II

A large school of hammerhead sharks swimming in blue water
A spotted eagle ray forages along the sandy seafloor near coral rubble
A diver photographs a dense school of tuna swirling in blue water
A diver comes face to face with a camouflaged frogfish on a coral outcrop

Protected as a national park and UNESCO World Heritage Site, the waters surrounding Cocos Island are home to abundant sharks, dolphins, rays, and approximately 50 species of endemic fish. Combined with the limited human land presence, Cocos routinely makes it onto top 10 lists for scuba divers around the world.  With the chance to dive 24 times during this trip, guests will spend plenty of time underwater.

Visibility can be over 80 feet (23 m) during the dry season (December to June). However, during the rainy season (May through November), divers are more likely to see hundreds of hammerhead sharks despite overall lower visibility. The average annual air temperature is 80 F (27 C). Light layers are recommended, especially for nighttime.

Conditions in Costa Rica allow for year-round diving. Water temperatures commonly range from 75 to 82 F (23 to 28 C), however, thermoclines occur at many sites and can cause greater fluctuations.

Those who typically wear a 3 mm wetsuit in tropical climates may want extra insulation for thermocline chills; most divers opt for at least 5 mm. In addition to thermoclines, divers should expect surge and currents. As such, this liveaboard is not suitable for beginners. According to regulations, night dives are not offered for Cocos Island.

Rental gear is available on board, as is nitrox certification. Note that not all dives provide direct supervision with an underwater guide. You and your dive buddy must be comfortable planning your own dive within the safety guidelines. However, staff will always be in the water, so buddies are welcome to stay near the staff if they wish. Sometimes a staff member will lead a group. Dives are conducted from a simple panga, launched from the main boat.

Excursions to the island are sometimes offered, usually including a hike to a lookout point, a natural pool, and the ranger’s station. This is a unique opportunity, as visitors to the island are few.

Highlights:

  • Impressive quantity and variety of sharks
  • Many endemic fish species
  • Uncrowded dive sites

Onboard the Okeanos Aggressor II

Twin beds and ensuite bathroom in an Okeanos Aggressor II stateroom
Dining and lounge area with table settings aboard the Okeanos Aggressor II
Twin beds with towel swans in an Okeanos Aggressor II cabin
Guest relaxing with a book on the sofa aboard the Okeanos Aggressor II

At 120 feet (36 m), the Okeanos Aggressor II accommodates 22 passengers within 11 staterooms. Two suites are available, one with a king bed and one with two twin beds that are fixed in place. Both have a 42-inch flat screen TV and minibar/fridge.

One master stateroom features a queen bed, and the other eight rooms have bunk beds with a double lower and a twin upper. All rooms have bathrobes, blow dryers, ensuite bathrooms, and individually controlled air conditioning. Bright walls and dark wood blend energizing and calming aesthetics for the best of both worlds.

On the sun deck, relax in the popular hammock or choose one of several loungers. Sip a complimentary beverage in the shady area as you take in the tropical surroundings. The grill/BBQ will waft sumptuous smells as you soak in the sun. The dive deck features individual dive lockers and two hot, freshwater showers. A dedicated camera table with a low-pressure hose is available, as well as separate rinse tanks for cameras and equipment.

Back inside the boat, the restaurant doubles as a lounge, with padded benches, armchairs, and a cozy couch corner. Two computer stations are available for downloading photos. Above the bar, a television is mounted for movie nights, and guests are encouraged to bring movies if they wish.

Onboard entertainment includes fish identification slideshows, movies, and games. A library of books (take one, leave one) is also available. Fish identification books are permanent fixtures. The ship’s boutique is available to peruse, selling t-shirts and other sundries.

If connecting to the outside world is a must for you, satellite e-mail is available onboard. However, charges are incurred for ingoing and outgoing e-mails. When floating around Cocos Island, you may experience intermittent cellular service.

Highlights:

  • Bathrobes and blow dryers in every room
  • Hot freshwater showers on the dive deck
  • Sunny hammock

Dining on the Okeanos Aggressor II

Crew member grilling food at sunset on the Okeanos Aggressor II deck
Chocolate dessert and wine served at sunset aboard the Okeanos Aggressor II
Formally set dining tables in the Okeanos Aggressor II restaurant

Staff put in extra effort to create fun, artistic edible decorations that are sure to impress and delight you. Complimentary beer and wine are offered throughout the journey. If you are particular about certain labels, pick up your favorites at the airport duty free shop.

Both cold and hot fare is available in the morning, and seasonal fresh fruit is a point of pride. Homemade breads, soups, and salads abound for lunch offerings. Dinners incorporate larger entrée selections with salads and homemade dessert. Meals are ordinarily served buffet-style, but table side service is common at dinner.

Expect mostly Western dishes with an international influence. The grill is put to good use for barbecues, and special occasions like birthdays are celebrated with impressive cakes. As with any dietary restrictions, guests should communicate with staff when booking.

Highlights:

  • Fresh fruit
  • Complimentary beer and wine
  • Special occasion desserts

Things we like:

  • Secluded location with abundant marine life
  • Hammock on the sun deck
  • Unlimited beer and wine included

Things we don't like:

  • High price tag for amenities included
  • 36-hour journey to/from Cocos can be choppy
  • Visibility under 80 feet (24 m) during rainy season
Key facts
Year built: 1985
Max divers: 22
Rental equip: Yes ($)
Camera station: Yes
Internet: No
Min logged dives: No minimum
Nitrox: Yes ($)
Aircon: Yes
Trip length: 8+ Nights
Price range: Luxury
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