The Oaxacan coast is one of the most important sea turtle nesting zones in the world. Hundreds of thousands of olive ridley turtles arrive here each year to lay their eggs, and the beaches around San Agustinillo — along with nearby Mazunte and the famous Escobilla beach — are ground zero for this phenomenon.
If you time your visit right, witnessing a turtle nesting event or a hatchling release is the kind of experience that stays with you for years. This guide covers everything: the biology, the timing, the practicalities, and how to experience it without being part of the problem.
The Species
Two sea turtle species are most relevant to visitors in San Agustinillo:
Olive Ridley (Golfina) — Lepidochelys olivacea: This is the star of the show. Olive ridleys are famous for their “arribadas” — mass nesting events where thousands of females come ashore simultaneously on the same beach over a period of several days. These events happen at Playa Escobilla (about 40 km from San Agustinillo) and are one of the most spectacular wildlife phenomena in Mexico. The turtles that feed along the coastline near San Agustinillo are often olive ridleys.
Green Turtle (Tortuga Prieta) — Chelonia mydas: Green turtles nest in smaller numbers on beaches throughout the region, including the beaches near San Agustinillo and Mazunte. They’re also the species most commonly seen while snorkeling in the bay, as they feed on seagrass beds close to shore.
Leatherback (Laúd) — Dermochelys coriacea: Rare but present. The world’s largest sea turtle occasionally nests on isolated beaches in the region. If you see one, consider yourself extremely fortunate.
When Turtle Season Happens
Turtle season on the Oaxacan coast runs from roughly late July through December, with the peak of olive ridley nesting in September and October.
Here’s a more detailed breakdown:
- July–August: The first olive ridleys begin arriving. Smaller individual nestings rather than full arribadas. Green turtles also active.
- September–October: Peak season. The largest arribadas at Escobilla happen during these months. The beaches around San Agustinillo see individual nesting on many nights.
- November–December: Nesting continues but tapers off. Hatchling releases become common as eggs from September nestings begin to hatch. This is often the best time to witness a hatchling release.
- January–April: Very few nesting events, but green turtles remain in the water feeding year-round. Snorkeling encounters with turtles are still common.
Where to See Turtles Nesting Near San Agustinillo
Playa Mermejita (2 km from Mazunte): This protected beach is one of the closest nesting sites to San Agustinillo. Individual olive ridley and green turtle nestings happen here throughout the season. Access to the beach after dark requires coordination with local conservation groups — don’t just show up at night.
Beaches near San Agustinillo itself: Nesting does occur on the main beach and on the small beaches around the rocky points. These events are less predictable than at Mermejita.
Playa Escobilla (about 40 km east of San Agustinillo): This is the world-famous arribada beach. During a mass nesting event, you can witness hundreds to thousands of turtles coming ashore in a single night. Access is managed through SEMARNAT (Mexico’s environmental ministry) and requires advance coordination. Tours from San Agustinillo and Mazunte run during peak season — ask your accommodation.
How to See Turtles Responsibly
This section matters. Irresponsible turtle tourism is a real problem on the Oaxacan coast, and your behavior during a turtle encounter has direct consequences for nesting success.
At night (nesting):
- Go with an authorized guide or through a recognized conservation program. Don’t go alone to nesting beaches after dark.
- No flashlights, phone screens, or flash photography. Artificial light disorients nesting females and causes them to return to the sea before laying, or it disorients hatchlings that use moonlight to find the ocean.
- Keep voices low. Sudden noise causes females to abort the nesting process.
- Stay behind the turtle and to the side — never in front. Looking into a turtle’s eyes while she’s nesting causes her to leave immediately.
- Don’t touch the turtle, sit on her, or try to interact with her in any way.
- If a female emerges and turns back to sea without nesting, human disturbance is usually why.
During hatchling releases:
- These are often organized events run by campamentos tortugueros (turtle camps). The campamento at San Agustinillo sometimes organizes releases open to visitors.
- Don’t touch hatchlings. Even with clean hands, oils and bacteria from human skin can harm them.
- Don’t place hatchlings in the water. The scramble down the beach is biologically important — it helps them orient to the Earth’s magnetic field, which they use for navigation for the rest of their lives.
- Keep the path to the water clear.
The Campamento Tortuguero
San Agustinillo has a community turtle conservation camp run by local cooperatives. These camps collect and protect eggs from nesting beaches, incubate them in protected nests, and release hatchlings in organized events.
Visitors are sometimes invited to observe hatchling releases, which are one of the most moving wildlife experiences imaginable — watching dozens of tiny turtles make their first scramble toward the Pacific as the sun goes down.
Ask at your accommodation about whether the local campamento is active during your visit and how to participate. Donations to these programs directly fund the conservation work.
Snorkeling with Turtles During the Day
Even outside of peak nesting season, sea turtles are present in the water near San Agustinillo year-round. Green turtles in particular feed on seagrass in the bay and around the rocky reef points.
Morning snorkeling at the east end of San Agustinillo beach (near the rocks) is one of the most reliable ways to encounter a turtle without any tour. Early morning, calm water, slow movement. Turtles here are accustomed to snorkelers and often continue feeding at close range if you approach calmly and without splashing.
This is, in many ways, even more intimate than a nighttime nesting event — you’re in the same water, at the same level, in their habitat.
Practical Information for Your Visit
Best months overall: For a combination of nesting events and good beach conditions, October and November are ideal. You get peak nesting season plus the chance to witness hatchling releases, while the main beach is still swimmable and the rains are tapering off.
Weather during turtle season: July through October overlaps with rainy season on the Oaxacan coast. Expect afternoon showers, high humidity, and occasional rough seas. Mornings are usually clear. This doesn’t ruin the experience — the rain often passes quickly — but it’s worth knowing.
Photography at night: Not possible without disturbing the animals. Save your camera for daytime snorkeling and hatchling releases in early evening light.
Booking: If visiting during peak season (September–October), book accommodation well in advance. The combination of turtle season and Mexican school holidays can fill places up quickly.
Why This Matters
The olive ridley sea turtle has rebounded from near-extinction thanks in large part to conservation work on the Oaxacan coast. Commercial turtle hunting was once devastating here — Mazunte was the site of the last legal sea turtle processing plant in Mexico, which closed in 1990 after massive pressure from conservation organizations.
The transformation of communities like Mazunte from turtle hunters to turtle protectors is one of conservation’s genuine success stories. When you visit with care, spend money with local cooperatives, and follow the rules around nesting beaches, you’re participating in the continuation of that story.
The turtles were here long before us — some species have existed for over 100 million years. A little humility goes a long way when you’re standing on the same beach where they’ve been returning for millennia.
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