The Ostional Wildlife Refuge (RNVSO) is a natural conservation area located on Ostional beach, in the district of Cuajiniquil, canton of Santa Cruz, province of Guanacaste, Costa Rica. It is an area that protects the nesting of various species of Pacific Ocean sea turtles, particularly the Kemp’s ridley. It was created in 1983 and has an area of 16 km, made up of the Ostional, Nosara, Peladas and Guiones beaches.
It is located about 360 kilometers from San José. It is administered by the National System of Conservation Areas (SINAC).
The arrivals are concentrated on the Ostional and Nosara beaches. In the other beaches, although they receive turtles, nesting occurs solitary and usually they are not as frequent or as abundant.
At Playa Ostional, four species of turtles come to nest:
Hawksbill turtle: which does so sporadically throughout the year.
Pacific green turtle or black turtle: which does it in a reduced way throughout the year.
Leatherback turtle: which does so in much greater presence than the previous ones between the months of October to April.
Kemp’s ridley turtle: which does so in large numbers both in the rainy season and in the dry season.
The last one, perhaps, is what makes this place so important, as this turtle, unlike the others, nests in masse during a defined period of time during each month of the year.
Specifically, they are usually 3 to 4 days and sometimes extend up to 7 days of the month and can reach up to 150,000 turtles, consecutively both at night and during the day. Hence, the observation of this phenomenon called “arribada” or “flota” has become so popular for Costa Ricans and foreigners who come to appreciate this wonderful phenomenon.