Ostional, Costa Rica offers 4 beaches perfect for sunbathing, surfing, swimming, and more. Ostional is known for the Ostional Wildlife Refuge, where the mass nesting of olive ridley sea turtles, known as "arribadas," occurs. The best time to travel to Ostional, Costa Rica, is from December to April, with average air temperatures around 85°F (29°C) and water temperatures near 82°F (28°C). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!