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Island Hopping Costa Rica

by Michael L. Smith


No, Costa Rica is not "that tropical island country" even though it has many of the wonderful qualities we associate with our perception of a South Pacific island paradise. But it does have, as part of its national territory, a number of significant tropical islands--and dozens of lesser ones. Several of them are very interesting, and a handful of them qualify as famous.

The islands in the Gulf of Nicoya and along the Pacific coastline are of the same sedimentary composition as the Nicoya Peninsula. The layers of sediment were put down between 40 and 80 million years ago. The islands were isolated from the surrounding terrain when the seas last rose. These islands and rock outcroppings have no particular geological uniqueness and tend to reflect their surrounding environment.


Most of Costa Rica's islands are in the Gulf of Nicoya. Their total land area is only about 40 square miles, but those few square miles harbor an interesting cross-section of climates and topography.


There are three significant exceptions to these sedimentary islands--Cocos, Caño and Violin. Cocos is the only Costa Rican island with volcanic origins. Caño is a product of plate tectonics--specifically, the subduction of the Cocos Plate beneath the Caribbean Plate pushed this land up from the ocean depths some fifty million years ago. Violin Island, in a river mouth of the Osa Peninsula, is a relatively young island formed by river sediments and the growth of a mangrove swamp.

No Trespassing

Costa Rica Islet

A handful of Costa Rica's islands are protected through the national parks system. Although having nothing of significance to offer as far as unique vegetation goes (with one outstanding exception), several are very important refuges for sea birds.

Perhaps the most well-known of Costa Rica's islands is Cocos, the world's largest uninhabited island. Geologically, it is the only outcropping from the submarine Cocos Ridge that runs from the Galapagos islands to the middle American Trench. This two million-year-old volcanic island is so unique, and considered so important, that it is virtually off-limits to the casual traveler and is protected by a resident guard. Its twenty square miles of tropical forests, rivers and plunging waterfalls, some 340 miles off the Pacific coast, is in the same class as the Galapagos islands. It harbors several endemic floral and faunal species and, like the Galapagos, is considered a natural laboratory for studying the evolution of different plant and animal species. When pirates discovered it during the 17th century, it quickly became a favorite hideout because of its total isolation.

Caño Island is a 740-acre biological refuge surrounded by five platforms of healthy coral. With regular sitings of hammerhead sharks, manta rays and sea turtles, it is becoming a favorite spot for scuba divers. Sitting ten miles off the western shore of the Osa Peninsula, its vegetation consists of very moist tropical forests, mirroring the onshore vegetation of the Osa and Corcovado National Park. It is archaeologically significant also, owing to the discovery of the remains of several pre-Columbian cemeteries, as well as evidence that the local Indians used it as late as 500 years ago.

The rugged, sixty-two acre Bolaños Island was declared a Wildlife Refuge in 1981 to protect the only known nesting sites in Costa Rica of the magnificent frigate and the American oystercatcher. It is also one of few nesting sites in Costa Rica for the brown pelican. The vegetation is classified as very dry tropical forest, like most of the Nicoya Peninsula. At low tide it is possible to hike the perimeter of Bolaños and observe several species of sea birds in the rocks.

Cabo Blanco Island

Named for the white guano deposits that cover it, Cabo Blanco Island is a rocky mound completely devoid of vegetation. This island, along with its onshore counterpart, was the first protected area in Costa Rica. Created in 1963 as a Strict Nature Reserve, it protects vitally important roosting sites for several sea birds such as the brown pelican, laughing gull, anhinga and magnificent frigate. It also harbors the country's largest colony of brown boobies. Access to the island is restricted, but it can be seen from the onshore part of the Cabo Blanco Strict Nature Reserve.

The trio of Guayabo, Pájaros, and the Negritos pair of islands, in the Gulf of Nicoya, are also protected because of their importance as roosting and nesting sites, as well as the cross-section of flora that grows on them. Guayabo is the largest of four known Costa Rican nesting sites for the brown pelican and is also a wintering site for the peregrine falcon. The Negritos Islands are covered with a semi-deciduous forest consisting primarily of frangipani, spiny cedar and gumbo- limbo. Several sea birds, including the brown pelican, roost there. Giant conches and oysters inhabit the surrounding waters. Pájaros island harbors a sampling of the nearby onshore vegetation and has an intertidal zone where rock oysters and barnacles abound.

Island Life

Costa Rica has other islands that are interesting for various reasons. The largest island in the territory is Chira. Sitting at the upper end of the Gulf of Nicoya, it is also the only one with a permanent human population. Although several smaller islands have residents, Chira is the only island with the necessary infrastructure--including electricity, medical services and schools--to support its two thousand inhabitants. The majority of the residents are fishermen or subsistence farmers. Another interesting fact about this seventeen-square-mile island is that about half of it is a protected mangrove swamp.

Costa Rica has a small island named Alcatraz, but it is insignificant and not very interesting. What is interesting is that until 1991, Costa Rica had its own version of the Alcatraz Island that North Americans are familiar with. San Lucas was a penal colony island sitting in the Gulf of Nicoya. This was by all accounts the most famous--and infamous--prison in Costa Rica. Its 117 year history is rich with tales of violence. The worst of society's undesirables were banished to this isolated, 2000-acre island. The prisoners essentially ran the community and fished, farmed and did all necessary domestic chores. Today, the crumbling prison walls covered with graffiti (often drawn in blood), the legends and tales of more than a century of past horrors and of escape and re-capture are all that remain. It is now possible to hire a boat in Puntarenas and visit San Lucas to get an idea of how those outcasts of society lived.

The most visited of Costa Rica's islands is certainly Tortuga. This island sits in the clear, turquoise waters of the Gulf of Nicoya and boasts beautiful white sand beaches lined with swaying palm trees. Its intrinsic beauty was realized long ago by the locals of the area. Several years ago the tourist industry discovered it. Now tour companies offer excursions to the island providing their guests a fantastic day of fun and adventure in the most sought after setting in the world--a tropical island paradise.

Violin Island is geologically unique in the context of Costa Rican islands. It formed as a delta at the mouth of the Sierpe River near Corcovado National Park. The island is mostly mangrove swamp and as such provides an important littoral area for numerous species of marine life.

Uvita Island

The only island on the Atlantic side of Costa Rica is Uvita, offshore from Limón. Historically, it is recognized as the spot where Christopher Columbus first landed on our coast in 1502, during his fourth voyage to the New World.

In Search Of . . .

Of the several dozen islands in Costa Rica, there are only between fifteen and twenty of significant size. However, many of the others of "insignificant" size are beautiful tropical locations sporting palms and beaches and clear waters. Local fishermen utilize them occasionally and you may find a tourist or two on one of them, but for the most part they are uninhabited and waiting.

If you care to hire a launch or fishing boat out of Puntarenas or one of the other coastal towns around the Gulf or along the Pacific coast, you can go exploring. You are sure to discover some beautiful spots that you will swear no one has ever been to before. It is very possible that you will find a special place on one of those islands--uninhabited, quiet, clear waters, white sand beaches, coconut palms swaying in a cooling sea breeze. A place that can become your tropical island paradise . . . at least for a few hours.

The author would like to thank Professor Gilbert Vargas, Director of the Geography Department at the University of Costa Rica, for his help in researching this article.

Updated on August 1, 1997 by M.L. Smith