By the time you read this we will be hundreds of miles off the coast of Costa Rica on board a live aboard dive boat called the M/V Argo (operated by Undersea Hunter) in the Pacific Ocean near Cocos Island National Park where, with any luck, we will find ourselves in the water surrounded by hammerhead sharks.

Cocos Island, an uninhabited island and national park 300 miles off the coast of Costa Rica. © copyright by Undersea Hunter Group
Cocos Island is the largest uninhabited island in the world and one of the most remote national parks in the world. The island is mostly rainforest covered (the only rainforest in the Pacific) and boasts more than 300 waterfalls, some plunging directly into the ocean.

There are more than 300 waterfalls on Cocos Island, some of them plunging directly into the Pacific. © copyright by Undersea Hunter Group
Cocos Island is also said to be the site of buried treasure, perhaps as much as a billion dollars worth. Pirates used Cocos as a sort of bank before the Costa Rican government took it over in the late 1800s. A few people have actually managed to get permission to search the island for the treasure—one man spent 19 years and millions of dollars but couldn’t find a penny.
Jurassic Park is said to have been based on a landscape inspired by Cocos Island. Treasure Island may have also been based on Cocos Island. President Franklin Delano Roosevelt visited Cocos Island three times and Jacques Cousteau called Cocos “the most beautiful island in the world” then he carved some graffiti into a rock on the shore and left.

Our home for 10 days, the M/V Argo live aboard dive boat. © copyright by Undersea Hunter
That’s all well and good but what we’re interested in are what dive geeks call pelagics–large rays and sharks. The waters around Cocos Island have the densest concentration of large marine predators including silky sharks, Galapagos sharks, reef sharks and more hammerheads than anywhere else in the world. Enormous manta rays and whale sharks are also seen here.

We hope to be in the midst of a school of hammerheads like this during dives around Cocos Island in Costa Rica. © copyright by Avi Klapfer
As if that’s not enough adrenaline, we may also get a submarine ride in the Undersea Hunter DeepSee submersible which takes two people at a time down to depths of 300, 700, or even 1,000 feet. It’s darker down there and the marine life gets weirder and weirder the deeper you go.

In search of even deeper creatures in the DeepSee submersible. © copyright by Undersea Hunter
Here’s a video about Cocos Island from the UNESCO YouTube channel.
Here’s more about travel in Costa Rica
I can’t wait to go to Costa Rica. I love their attitude to ecotourism and everything they do for the animals. It’s a really beautiful country. You’re lucky!
They are really amazing creatures aren’t they? We saw a large school of hammerheads near the island Layang Layang, close to Borneo. It was such a cool and almost surreal experience.. Very curious to know whether you did see them at cocos island. Hope you had fun anyways!
awesome post on Cocos island and one that inspires me to also dream about Costa Rica. I have never been outside of Asia but this post made me dream to one day, visit Costa Rica. Just love this post.
I love hammerheads, and hope you see a school like in the picture above. I got into scuba diving in part because of a National Geographic video about Cocos Island. And while I’ve seen some sharks while scuba diving, I’m still looking forward to the day I can check dove with a hammerhead off the list.
We’ve been to Costa Rica twice, but never made it out Cocos Island. Sounds amazing! I’ve only seen hammerheads once, of Hawaii’s Big Island, and only from above. There were maybe 10 on the surface, but our guide (a world-class free diver) jumped in and got photos revealing more than 100 sharks below! Sadly, they wouldn’t let us jump in, since we were supposed to be snorkeling in Kealekekua Bay. Hope you guys get some great diving opportunities, and the sub dive sounds incredible!
Awesome article! I had no idea the Cocos islands even existed. That really sounds like a once in a lifetime experience though. Did you run into as many sharks as you hoped.