How to See Tons of Turtles at Ostional Wildlife Refuge in Costa Rica

Olive ridley sea turtle arribada at Ostional Wildlife Refuge in Costa Rica
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The Ostional Wildlife Refuge in Costa Rica is the location of a spectacular natural phenomenon – the mass nesting of Olive ridley sea turtles. Called “arribadas” in Spanish, tens of thousands of turtles come to lay their eggs on Ostional Beach, an 18km wildlife refuge on the Pacific coast of Costa Rica. If you are in Costa Rica during an arribada, bring your kids to see the turtles at Ostional Wildlife Refuge.

How to See a Sea Turtle Arribada in Ostional, Costa Rica

What is an Arribada Like?

We visited on the second night of an arribada in late November 2018. At sunset, there were roughly 3,000 turtles nesting on a 2km stretch of beach.

Turtle nesting at Ostional Wildlife Refuge peaks during the rainy season (August to December). Arribadas occur about once per month, typically during the darkest nights before the new moon. The average arribadas lasts 2-4 days. Check the official Ostional Guide Association Facebook page for current arribadas status.

An arribada of Olive Ridley sea turtles at Ostional Wildlife Refuge in Costa Rica
We were surprised to learn that Olive ridley turtles live solitary lives at sea. Only at nesting time do they gather in these large groups.

Watch out for incoming turtles! Do not stand in front of turtles coming out of the water. If they get scared, they will return to the water. Once a turtle starts nesting, she is focused and little will disturb her, including photos and active children.

One turtle takes about 30 minutes to complete a nest – quick enough for kids to watch the whole process without losing interest. The female heaves herself out of the ocean and over the high tide line. She then digs a hole. Because so many females nest at Ostional during an arribada, they may nest on top of a previously laid nest. If that happens, the female uses her flippers to lift older eggs out of the sand before laying her own.

Olive Ridley turtle lays eggs at Ostional Wildlife Refuge in Costa Rica
One female lays 80-120 white eggs the size of a ping pong ball.

After the eggs are laid, the female fills the hole, compacts the sand with her flippers, and then uses her flippers to shuffle the sand in an attempt to camouflage the nest from predators. Then she returns to the sea.

Tell Me More About Olive Ridley Turtles!

Olive Ridley sea turtle at Ostional Wildlife Refuge in Costa Rica
Costa Ricans call them “Lara” because they resemble a green parrot of the same name

The Olive ridley turtle is the smallest sea turtle in the world. One turtle may lay eggs as many as 3-5 times in one year, but then waits 2 years between nestings.

Olive ridley eggs take approximately 45 days to hatch. On average, 90% hatch, 60% make it to the water, and 1% will survive to adulthood and return to nest. The survivors return to the same beach where they were hatched.

Why do so many turtles nest at Ostional beach? The black sand is a good temperature for egg survival and camouflages nests against predators. The steep slope of the beach makes arrival and departure easier for the females.

Olive ridley sea turtles enter and exit the ocean at Ostional Wildlife Refuge in Costa Rica
Female turtles cross paths as they enter and exit the ocean

Should I Take a Tour?

Whether you visit with a tour group or on your own, a local Ostional guide must accompany you onto the beach. A tour group is recommended if you do not have your own transportation. For example, a tour from Playa Sámara to Ostional cost $45/person and included transport, guide, Ostional guide, and fresh fruit (2018 prices). Children pay the same price as adults.

A guide from the Ostional Guide Association shares her knowledge with a family
Our local guide was quiet to start with, but once we started asking questions she was happy to share her knowledge.

If you have your own transportation, you can reserve a guide in advance via the official Ostional Guide Association Facebook page or hire a guide at the Guide Association office in town. We recommend organizing one in advance, if possible. The guides are extremely busy during arribadas.

Photo tip! If you organize your own visit, consider the timing of the sunset. You can see the most and get the best photos before sunset, which will be around 5:30 pm all year.

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