Costa Rica is one of the best places in the world to witness sea turtle nesting. The country hosts multiple species across both coasts, but the most accessible and dramatic experience is the olive ridley mass arrival — known as the arribada — that takes place on the Nicoya Peninsula of Guanacaste, just a short drive from Sámara.

Here’s everything you need to know to plan a responsible, memorable experience.

Which turtles nest in Guanacaste?

The primary species in this region is the olive ridley sea turtle (Lepidochelys olivacea). They’re smaller than leatherbacks or green turtles, but what makes them extraordinary is the synchronized mass nesting behavior. During an arribada, hundreds to thousands of females come ashore simultaneously over 3–5 nights to lay their eggs. This happens at a handful of beaches in the world, and Ostional — 30 minutes from Sámara — is one of them.

Ostional Wildlife Refuge

Ostional is the most significant olive ridley nesting site on Costa Rica’s Pacific coast. The arrivals are governed by tides and moon phases — typically occurring in the days just before the new moon. Timing is monitored by local guides, and our Turtle Nesting Tour in Ostional adjusts departure times based on nesting activity reports each month.

The tour is 4 hours, departs from Sámara or Puerto Carrillo, includes round-trip transport, a bilingual guide, refuge entrance fee, and light snacks. You’ll need water-friendly footwear as the route crosses a small river. Price: $85 per person (adults and children ages 5–10).

On non-mass arrival nights, you can still observe solitary nesting females and hatchlings at the refuge — so even if you don’t hit the full arribada, you’re unlikely to leave disappointed.

Corozalito as an alternative

For a more intimate experience with smaller groups, our Turtle Nesting Tour in Corozalito visits a quieter refuge nearby. It’s 3.5 hours, $68 per person, and operates under the same ethical guidelines — red-light torches, no flash photography, quiet observation. The smaller scale means fewer turtles but a more personal encounter.

What to expect on the tour

You’ll be picked up from your hotel in Sámara or Puerto Carrillo after dark. At the refuge, your bilingual guide will explain olive ridley biology and the importance of conservation before leading you onto the beach. You’ll observe females laboring through the surf, excavating nests with their flippers, and depositing eggs — a ritual that has continued for millions of years. No flash photography is permitted, and guides maintain respectful distance at all times.

Best time of year

Olive ridley arrivals at Ostional happen year-round, but peak season runs roughly July through November, during the rainy season. The most spectacular mass arrivals tend to coincide with the wettest months. That said, every month brings a nesting window — check with us before booking and we’ll confirm the next expected arrival dates.

Ethical guidelines

Never touch a nesting turtle without guide permission. No white lights or flash photography on the beach. Dark clothing is required. Don’t use cell phone flashlights — the blue light disorients turtles and hatchlings. Book through a licensed operator that works with certified local guides and contributes to refuge conservation.

Both of our tours meet these standards. If you want to add a turtle nesting experience to your Sámara itinerary, reach out via our Free Vacation Planning service and we’ll coordinate the timing around your stay.