Ostional Wildlife Refuge was created in 1984 for the protection and conservation of this primary Olive Ridley Turtle nesting area. The beach itself is located near Playa Nosara, on the Nicoya Peninsula, in the Guanacaste Province. The refuge encompasses some 248 hectares (613 acres). Ostional Wildlife Refuge is also utilized by the gigantic Leatherback and Green Turtles from October through December for nesting purposes as well, though not nearly in the same numbers.

Ostional Wildlife Refuge is not only protected by the Costa Rica government, but also by the remote location. The refuge can only be accessed when weather permits in the dry season. Visitors can reach Playa Ostional by crossing shallow rivers from the north or the south between the months of mid December through early April. These rivers rise making them impassible between the months of May through November. Of course, there are times during the Green season that allow for crossing. It is however, a good rule of thumb not to count on crossing at this time.

Contradictory to the aforementioned accessibility, the best time to observe turtle nesting is during the green season. The best months are June through December. "Arribadas", which means arrival, happen at least once per month following a full moon. During arribadas, hundreds of thousands of Olive Ridley Turtles can arrive at the same time on this small stretch of beach during the green season. Tens of thousands can arrive during the dry season. The largest recorded arribada happened in 1995, when an estimated 500,000 female olive ridley turtles came ashore to lay eggs.

Ostional Wildlife Refuge is protected by locals that were hired to watch over the eggs and nesting areas from human predation. The entrance fee to Ostional Wildlife Refuge was recently raised to $10 for foreign visitors.