It took more than a decade, but we finally made it to Cocos Island National Park in Costa Rica. Ever since we heard about the island’s history (beloved by both pirates and Presidents), remoteness (it takes days to get there), and sharks (tiger sharks, silky sharks, whale sharks, and endangered scalloped hammerheads congregate here in big numbers) we’ve been dreaming of SCUBA diving around Cocos Island.

Hammerhead Sharks - Cocos Island, Costa Rica

Groups of endangered hammerhead sharks are regularly seen by divers in the waters around Cocos Island in Costa Rica. Photo courtesy of the Undersea Hunter Group

Part of the reason it took us so long to get to Cocos Island is that it’s 350 miles (560 km) off the coast of Costa Rica. Unfortunately, we did not go for the Chitty-Chitty-Bang-Bang version of our truck so our only option, like most people, was to travel to Cocos Island on a live aboard dive boat. So that’s what we (finally) did.

Our home during a 10 day trip to Cocos Island was Undersea Hunter‘s M/V Argo live aboard dive boat. It’s best to think of the Argo and its nine cabins as a stylish, floating, all-inclusive hotel that you can never leave except to go diving. Heaven.

Unfdersea Hunter MV Argo - Cocos Island, Costa Rica

The swanky M/V Argo live aboard dive boat, operated by Undersea Hunter, was our home on the high seas during a 10-day diving trip to Cocos Island in Costa Rica.

Pirates and Presidents

Like so many treasures, pirates claimed Cocos Island as their own, first as a life-saving source of fresh water and wood for ship repairs, then as a bank. Many believe that hundreds of tons of gold, religious artifacts and other ill-gotten riches worth billions of dollars by today’s standards remain hidden on the island where pirates buried their loot long ago.

Cocos Island panorama Undersea Hunter Argo

Panorama of Cocos Island in Costa Rica with the M/V Argo in the right foreground (click to enlarge).

President Franklin Delano Roosevelt made three trips to Cocos Island in search of a
different kind of treasure. In 1935, during his first visit to the island, President
Roosevelt caught a 110 pound (50 kilo) sailfish. The fish was shipped back to the United States where the avid fisherman had it mounted and hung in the White House.

Pirates maintained their unofficial ownership of Cocos Island until 1832 when Costa Rica claimed the land. Cocos Island National Park was created in 1978 and made a UNESCO World Heritage Site in 1997.

Costa Rican flag - Cocos Island, Costa Rica

Rangers had just placed this Costa Rican flag on a hill above Chatham Bay on Cocos Island when we visited.

“The most beautiful island in the world”

When Jacques Cousteau saw Cocos he proclaimed it “the most beautiful island in the world.” He also carved the name of his research vessel into a rock on the shore of one of the bays that ring the island (a stunt that’s now prohibited).

Cocos Island rock inscription Jacques Cousteau's ship Alcyone

This rock inscription marks Jacques Cousteau’s visit to Cocos Island which he called “the most beautiful island in the world.”

The rocky island’s remoteness, jagged angles, 300 waterfalls and deep green lushness have inspired movie directors and authors too. Staff on board the Argo, pointed out one particularly elegant waterfall which, they said, appears in the opening scenes of the original Jurassic Park blockbuster. Robert Louis Stevenson’s Treasure Island may have been set on Cocos Island.

Cocos Island, Costa Rica

One of the more than 300 dramatic waterfalls on Cocos Island–this is not the one used in Jurassic Park.

While hiking on the island (there’s a ranger station and a couple of trails) it’s easy to imagine rogue dinosaurs and Long John Silver lurking in the cover of the large-leafed guaruma trees, giant ferns and vines which thrive in the rain forest climate.

Welcome to Cocos Island - UNESCO

Meet Cocos Island National Park ranger Geiner Golfio who looks a lot like a young Fidel Castro.

Waterfall - Cocos Island, Costa Rica

The rocky coast line of Cocos Island in Costa Rica.

Cocos Island

Cocos Island in evening light after another satisfyingly sharky day of diving.

They don’t call Cocos “Shark Island” for nothing

Cocos is sometimes called Shark Island because of the dense concentrations of tiger sharks, silky sharks, scalloped hammerhead sharks, enormous manta rays, reef sharks, Galapagos sharks, and even whale sharks in the water here. On a recent trip to Cocos, divers on the Argo also saw killer whales–a real rarity.

Those lucky enough to dive around Cocos (that would be us) are virtually guaranteed up-close encounters with most of these exciting sea creatures. But you’ve got to earn it.

Captain Undersea Hunter's MV Argo - Cocos Island

The captain of the M/V Argo live aboard dive boat was good at the helm and even better on the dance floor.

It takes about 35 hours to reach Cocos Island from mainland Costa Rica and the trip is through open ocean which can get rough. We went through one storm but, in general, our passage to Cocos was relatively calm. Karen did try a new seasickness pill called Bonine which lasts for 24 hours and didn’t seem to cause drowsiness like Dramamine does.

Instead of puking, we spent the crossing getting to know the awesome staff and dive masters, utterly charming captain, fabulous cooks, and the other divers on board. That’s where things can get tricky. If your live aboard shipmates are jerks you’re stuck with them underwater and topside.

Thankfully, the divers on the trip with us were beyond awesome and included Manuel Lazcano, an acclaimed underwater photographer and videographer and dive instructor who was on his 35th trip to Cocos along with a bunch of his super-cool friends from Mexico City. There was also a Swiss diver named Guido (true story), the coolest (in every sense) Texan ever, and a Costa Rican father and son physician team.

Cocos Island dive group

Best dive buddies ever: the crew and dive guests on our Undersea Hunter trip to Cocos Island in Costa Rica.

But we weren’t there for the cushy live aboard or the terrific company. Bring on the sharks!

Cocos Island is not for newbies

There is no doubt that Cocos Island is only for experienced divers. The water can be very cold and most dives are around 100 feet (30 meters) deep, sometimes more. Plus, you’ve got to be comfortable being surrounded by sharks.

There’s also a lot of current at Cocos Island dives sites–that’s part of what attracts the sharks. Both of us have done nearly 200 dives and we’ve never, ever worn gloves while diving. Normally dive gloves are banned to discourage touching anything while you’re down there. However, it soon became clear why gloves are a necessary accessory for Cocos Island diving.

SCUBA diving Cocos Island - backwards roll

Us ready to get wet and see some sharks during our dive trip to Cocos Island in Costa Rica.

Where are all the hammerheads?

Somehow we managed to see exactly zero hammerheads during our first day of diving which, in the dive-centric environment of a live aboard, includes up to five dives a day. We’re not naive. We know that it’s impossible to guarantee wild animal sightings but other divers saw hammerheads at other dive sites (we whined) and we went to bed feeling a little big gyped.

That didn’t last long. Our first dive on our second day at Cocos was at a site called Dirty Rock which is marked by a huge rock that juts out of the ocean. This rock is used by frigate birds and boobies as a resting spot and their poop has made the rock dirty, hence the name.

Waiting for hammerhead sharks - Cocos Island

Eric and Karen clinging to rocks against strong current in order to maintain our position near a cleaning station regularly visited by sharks.

As the skiff which took us from the Argo to our dive sites stopped at Dirty Rock we all back-rolled over the side and dropped as quickly as possible to about 100 feet (30 meters) under the surface of the water, re-grouping at a known cleaning station. Sharks regularly cruise through these spots where cleaner fish congregate, ready to gently remove parasites from the predators’ skin.

Oh, that’s what the gloves are for…

Another thing sharks like is current and lots of it. During most dives, we all scrambled to find a chunk of rock to hold on to so that we could maintain our positions and not get swept away by the wicked current. We can tell you that we were very glad we had gloves on to prevent the sharp rock and coral from cutting our hands to shreds as we held on tight. We were also glad that everyone who dives with Undersea Hunter is given a small emergency pack which contains a GPS device which would allow the Argo’s captain to quickly and accurately find you if you did get swept away.

Then it happened. First one then dozens of hammerheads emerged out of the deep blue. They were above us, below us and right in front of us slowly cruising in lazy laps around the submerged base of Dirty Rock (bits of which we were all still clinging to).

Cocos Island Hammerhead shark

Hello hammerhead! Photo courtesy of the Undersea Hunter Group

The hammerheads weren’t exactly scared of us but they weren’t happy to see us either. Despite our efforts to duck behind the rocks we were clinging to and peer discretely at the hammerheads, they would spot us (or our bubbles) sooner or later and dart off as if we’d just poked them in the nose. A few bolder hammerheads waited until the very, very last minute to dart away as if they were as curious about us as we were about them.

SCUBA diving with Hammerhead sharks - Cocos Island

That’s Eric in the lower lefthand corner and that’s a hammerhead veering off sharply to the right just a few feet from him. Photo courtesy of Rodrigo Roesch de Bedout

Though we would have been content to stay put watching the hammerhead show forever, after about an hour it was time to return to the zodiac and prepare for the second dive of the day. To say we were thrilled by our very first encounter with hammerheads would be a criminal understatement. And there were more thrills to come.

Cocos Island is not just about hammerheads

Still buzzing from the hammerheads at Dirty Rock, we started our second dive of the day at a site called Punta Maria where we saw more hammerheads and an enormous, lumbering Galapagos shark, another first for us.

The third dive of the day, at a site called Pajara, was filled with moray eels (one of them more than six feet, or two meters, long), cowfish, pipefish and enormous lobsters. We capped the day off with a shallow night dive where we watched reef sharks feeding just a few feet from us.

Cocos Island Eagle Rays

A flock of spotted eagle rays glides by overhead giving us a good look at their funny faces. Photo courtesy of the Undersea Hunter Group

Just another day at Cocos Island

Our days continued like this for a week with unseasonably warm water and extremely reliable shark encounters including dozens more hammerheads, the largest group occurring at a dive site called Alcyone where we also saw the rare and very violent spectacle of mating white tip sharks. Suffice to say, you’re glad you’re not a female white tip shark.

We saw more Galapagos sharks and even a few tiger sharks which got our adrenaline pumping more than any of the others given their size, great-white-like profile, and reputation for aggression.

Tiger Shark - Cocos Island, Costa Rica

A massive tiger shark dwarfs the diver below it. Photo courtesy of the Undersea Hunter Group

For the last dive of our trip our group returned to the Dirty Rock dive site where it all began. Again, we descended to the cleaning station at about 100 feet (30 meter) and, again, the hammerheads came out to play. Soon, more than 25 hammerheads were venturing closer and closer until they were near enough to make eye contact. After a week in the water with them they seemed to be getting a bit more comfortable with us.

All told, we spent more than 20 hours underwater during our Cocos Island trip and saw hundreds of sharks all at close range. Though the manta rays and whale sharks eluded us, they were seen by other divers on the Argo and it’s good to save something for next time. We now totally understand why Manuel has been back to dive Cocos Island 35 times and we’re already dreaming of our return.

Environmental show down

One of the reasons so many sharks are drawn to Cocos Island is because of unique mini mountains on the sea floor called the Las Gemelas seamounts. When deep currents hit these seamounts nutrient-rich water is pushed toward the surface attracting schools of fish and the predators who love them. Fishermen favor the area for the very same reason and continue to ply the waters illegally.

Read more about the environmental triumphs and challenges in the area in the travel feature we did about Cocos Island for the Minneapolis Star Tribune.

Bridge on Cocos island made from confiscated fishing gear

Karen crossing a bridge on Cocos Island which rangers constructed entirely out of equipment confiscated from fishermen working illegally in the protected waters around Cocos Island.

Wait, there’s more!

As if being surrounded by sharks wasn’t exciting enough we also joined the submariners club while we were at Cocos Island after taking a trip down to 300 feet (91 meters) below the surface of the ocean in a custom made, multi-million dollar submersible called the DeepSee.

Cocos Island sunset

Sea birds and sunsets cap off long days of diving around Cocos Island in Costa Rica.

Cocos Island travel tip

You may be wondering why there is no underwater video in this post. Of course we wanted video so we took our GoPro HD Hero camera with us on our dives and filmed away. It wasn’t until we screened the footage that we realized that the out-of-the box waterproof housing that comes with your GoPro HD Hero or GoPro HD Hero2 creates distorted, out of focus footage underwater. If you have one of those models and want to capture video underwater you must use the GoPro Dive Housing.  The housing that comes with the new GoPro HD Hero3 camera works as a dive housing.

The blurry footage below will show you what we’re talking about.

We didn’t spend all of our time underwater. The video below was taken during some hikes and swims on Cocos Island itself.″

Here’s more about travel in Costa Rica

Here’s more about Island Travel


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