Scuba Diving in the Pacific: Palau, Galapagos & Cocos Island

Exploring the Best Scuba Diving in Palau, the Galapagos, and Cocos Island, Costa Rica With Aggressor Adventures

The Pacific Ocean is large enough to hold every continent on Earth with room left over. Across that much open water, the most memorable dive sites are often the most isolated, like small islands and underwater mountains where deep currents rise to the surface and carry food up from below. That food draws in schools of fish, and the fish draw in sharks, rays, and other large animals. Scuba diving in the Pacific offers a mix of conditions that few other regions can’t match.

In the eastern Pacific, cool currents flow past the Galapagos and Cocos Island, where divers often wear thicker wetsuits and see schools of hammerhead sharks along the walls. In the western Pacific, Palau sits in warm tropical water surrounded by coral reefs, limestone islands, and historic World War II sites.

Aggressor Adventures® has offered liveaboard trips to Cocos Island since 1988. Today, Aggressor yachts sail to Cocos Island, the Galapagos, and Palau, and each destination offers a different kind of diving. Read on to learn what each trip includes, and we hope to welcome you on board.

Why Pacific Diving Belongs on Your Bucket List

The Pacific is one of the best places in the world to dive with large marine animals. Schools of hammerhead sharks gather at Cocos Island and in the northern Galapagos, and whale sharks pass through both areas during parts of the year. Palau adds manta rays, reef sharks, and some of the most colorful coral in the region.

The cooler water in the eastern Pacific is part of the appeal. It brings nutrients that support large schools of fish, and those schools attract the sharks and rays that divers travel so far to see. If you have been waiting to see schooling hammerheads for yourself, the Pacific is the place to plan your trip.

Why Aggressor Liveaboards Are the Best Way to Dive the Pacific

Some of the Pacific’s best dive sites cannot be reached on a day trip. Cocos Island sits 342 miles off the coast of Costa Rica, and the islands of Wolf and Darwin lie far to the north of the main Galapagos group. On an Aggressor liveaboard, the yacht carries you to these remote sites and stays nearby, so you can dive several times a day and return to chef-prepared meals between dives.

Aggressor Adventures® has spent more than four decades refining small-group adventure travel, and its Pacific fleet reflects that experience. Here is what each destination has waiting for you.

Galapagos Aggressor III: Wolf, Darwin, and Cooler Water

The Galapagos became an Aggressor destination in 1993, and the Galapagos Aggressor III runs Thursday-to-Thursday charters through some of the most protected waters in the Pacific. The marine reserve around Wolf and Darwin covers about 15,000 square miles and is closed to fishing. Darwin’s Arch, the famous rock formation near Darwin Island, collapsed in 2021, but the two pillars that remain still mark one of the most exciting dive sites in the islands.

Here is what you can expect when scuba diving in the Galapagos with Aggressor:

Four Dives a Day: Guests enjoy two morning dives and two afternoon dives, along with two land excursions during the week.
Schooling Hammerheads: From December through May, the water is warmer and the schools of hammerhead sharks tend to be larger, along with manta rays and eagle rays.
Whale Shark Season: From June through November, the water is cooler and whale shark sightings are more common.
Unique Wildlife: Divers may also see playful sea lions, marine iguanas feeding on algae, and ocean sunfish in the cooler months.
Cooler Water Temperatures: The water ranges from 60° to 75°F from June through November and from 70° to 86°F from December through May, so a 5 to 7mm wetsuit is recommended.
Dive Details: Depths range from 40 to 130 feet, and all dives launch from two 8-foot by 20-foot tenders. Night diving is not offered.

If you would like to see the Galapagos from below the surface as well as on land, the Galapagos Aggressor III is ready to welcome you.

Okeanos Aggressor II and Cocos Island Aggressor: Diving Costa Rica’s Remote Island

Cocos Island has been an Aggressor destination since 1988, and two yachts, the Okeanos Aggressor II and the Cocos Island Aggressor, now make the trip from Puntarenas, Costa Rica. The island is uninhabited and covered in steep cliffs, waterfalls, and dense rainforest, and it has often been compared to the island in Jurassic Park. Below the surface, it is known for large schools of hammerhead sharks.

Here is what to know about scuba diving at Cocos Island with Aggressor:

The Crossing: The island sits 342 miles off Costa Rica’s Pacific coast, and the crossing from Puntarenas takes about 36 hours each way.
Charter Options: Eight-night charters average about 15 dives, 10-night charters average about 21 dives, and 12-night charters average about 27 dives.
Sharks in Large Numbers: Divers regularly see schooling hammerheads and large numbers of whitetip reef sharks, and tiger sharks are sometimes seen as well.
Other Big Animals: Manta rays, tuna, and whale sharks also visit the island.
Water Conditions: Temperatures range from 72° to 82°F, with cooler layers of water at depth, so a 3 to 5mm wetsuit is recommended.
Dive Details: Depths range from 55 to 110 feet, and all dives are made from two 8-foot by 22-foot tenders. Night diving is not currently offered.

For divers who want to see schooling hammerheads in one of the most remote places in the Pacific, a charter to Cocos Island is well worth the journey.

Palau Aggressor II: Rock Islands, Manta Rays, and History

Palau has been an Aggressor destination since 1996, and the Palau Aggressor II offers a very different side of scuba diving in the Pacific. The water averages 82°F, so a 3mm wetsuit is usually enough. Above the surface, the mushroom-shaped Rock Islands rise from the lagoon, and below it, divers explore coral reefs, channels, blue holes, caves, and World War II wrecks.

Here is what a week of scuba diving in Palau with Aggressor includes:

Charter Schedule: Seven-night charters run Sunday to Sunday, with four dives a day from Monday through Friday, three night dives, and a half day of diving on Saturday.
Easy Entries: Dives launch from an 18-passenger dive skiff that is lowered by a hydraulic cradle.
Famous Dive Sites: Well-known sites include Blue Corner, German Channel, and Ulong, where currents bring in reef sharks and large schools of fish.
Manta Season: From December through March, guests may see as many as 20 to 30 manta rays.
Schooling Fish: February and March bring large schools of Moorish idols and unicornfish.
Experience Level: Palau’s currents can be strong, so the diving is best suited to divers with some experience.

Palau also offers two well-known land and snorkel excursions. The Peleliu historical land tour visits the site of the Battle of Peleliu, one of the costliest battles fought between American and Japanese forces in the Pacific during World War II. Jellyfish Lake, which recently returned to Palau Aggressor II itineraries, is a marine lake where guests snorkel among golden jellyfish. In peak years the lake has held millions of these jellyfish, and their sting is too mild for most swimmers to notice. Scuba diving is not permitted in the lake, so this visit is a snorkel-only experience.

If you are looking for warm water, manta rays, and a trip that combines diving with history, we would love to welcome you aboard the Palau Aggressor II.

Plan Your Pacific Adventure With Aggressor

Scuba diving in the Pacific rewards divers who are ready to travel a little farther for big encounters. Aggressor Liveaboards® take you to remote islands and keep the yacht close to the dive sites, while the crew manages the logistics and the chef prepares your meals. Whether you are interested in the hammerheads of Cocos Island, the whale sharks of the Galapagos, or the manta rays of Palau, there is an Aggressor yacht built for that trip. Aggressor Detours® can also arrange your airfare, hotels, transfers, and pre- or post-trip excursions, so your journey is simple from start to finish.

We invite you to choose the destination that fits your goals and plan your Adventure of a Lifetime® with Aggressor Adventures®.

Check rates and availability today to reserve your Pacific liveaboard trip.

The Adventure Atlas Series | Scuba Diving in the Pacific