This reserve is part of the Tempisque Conservation Area, along with Isla Negritos Biological Reserve (covering the two islands) and Los Pájaros Biological Reserve.
They are located in the Gulf of Nicoya facing Playa Naranjo, and can be seen from on board the Puntarenas ferry on its way to and from Paquera.
This island faithfully protects the many species of migratory birds who visit it during winter to nest. Some of the best-known species include the brown pelican (the island is home to one of the largest populations in Costa Rica), seagulls, peregrine falcons, white-tipped doves and boobies. Approximately 200 species of birds call Isla Guayabo home.
The Isla Guayabo Biological Reserve, which juts out 50 m above the surface of the water, extends over a total area of 15 hectares and is located 8 km from Puntarenas. The island used to be more imposing, but the passage of time has caused it to slowly disappear beneath the waves, leaving only its very tip above the water.
The island is mainly comprised of sedimentary rocks and is covered in shrubs and small thorny plants in some areas. Trees like the guaco and higuerón are common on the island, as well as the coyol and viscoyol palms.
Several species of crustaceans also inhabit the island, including fiddler crabs, European green crabs, giant conches, oysters and a wide variety of fish and insect species.
The region experiences a dry season from January to March. Currently, it is not possible to enter or walk on the island, with only boat visits allowed due to the conservation and protection rules in effect. However, you can watch birds and see the nesting sites up close.