World’s most important nesting sites of the olive ridley sea turtles

The beach of Ostional is the scenery for a rarely-seen biological wonder. The week before the new moon hundreds, and sometimes thousands of sea turtles come to one specific mile of beach at Ostional to dig their eggs into the black, volcanic sand. Costa rider Campervan tells you all the story!!

Some days or weeks before the mass nesting, the “flotilla”, an increasing number of turtles, congregates close offshore.

After some days, prompted by some secret signal, the “arribada” will begin. At first, a few hundred turtles will come out on the beach, followed by a steady stream of animals for the next three to seven days.

From August through December arribadas occur regularly once, sometimes even twice a month and the number of nesting females is in the range of hundreds of thousands as opposed to tens of thousands for the dry season months.

The largest “arribada” thus far recorded in Ostional, took place in November 1995 when a calculated 500 000 females came ashore.

Used to live in the ocean, the turtles painfully drag their heavy bodies over the beach until they get over the high tide line. There, flicking clouds of sand, they dig a nest with their flippers to deposit around 80 – 100 soft-shelled, white eggs, the size of a ping pong ball.

Throughout a five-day, arribada nesting turtles will leave up to 10 million eggs on the beach of Ostional.


Amazingly, Ostional is the only beach in the world where harvesting turtle eggs is legal. Scientists found out that most of the eggs deposed in the first nights of an arribada are destroyed by subsequent turtles who dig their nests.

Therefore, since 1987, the government of Costa Rica allows the community of Ostional to harvest the doomed eggs on the first three days of an arribada. In return, the villagers protect the turtles, clean debris from the beaches, and patrol day and night for poachers.

The baby turtles hatch within 45-54 days depending on incubation temperatures, which will also determine if they will become male or female. They face varying degrees of success in each of the clutches that are laid in large groups to increase their success in surviving.

As soon as the hatchlings have struggled out of the sand, the race to the ocean begins. With eyes barely opened, the mini turtles smell the breeze and instantly know the right direction.

Women and children from the community of Ostional accompany the hatchlings as they clamber toward the sea, protecting them from dogs and vultures.

Having reached the ocean, the mini sea turtles still aren’t safe – the next cast of predators awaits them underwater.

Most hatchlings don’t reach the age of maturity which takes 10 – 15 years, but those who make it will remember their home beach. Adventurous turtles may paddle across the Pacific ocean as far as India but their impressive natural navigation system steers them back to their place of birth in Ostional where they will lay their eggs again on the black sanded beach, as their mother once did.

A lot of places near Ostional are available to drop your camper. Be the first to camp close to the turtle, now it’s possible with a Costa Rider campervan.

Ready to meet the sea turtles on your campervan? Reserve here now.