The Turtle Calendar: When Nesting and Releases Happen

The Oaxaca coast is one of the world's great sea-turtle places, and it is not a secret. From Mazunte east past Puerto Escondido to the bays of Huatulco, the same beaches that make you slow down are the ones turtles have been using for generations. What surprises most visitors is the timing. Sea turtles here do not nest in a short, tidy season you can read off a poster. They show up over months, in pulses, and which pulse you get depends on what you are hoping to see.

The place

Why this coast is a turtle place

Drive the length of the coastline between Mazunte and Huatulco and you will notice something most tourist coasts have lost: stretches of sand with nothing on them. No hotel. No palapa row. Just surf, jungle, and the bones of a palm tree. That is precisely what turtles need. Nesting mothers want a beach they can reach, a night dark enough to hide in, and sand warm enough to incubate eggs through. This coast has all three, and it has kept them because the villages here were too small and too isolated to pave them over.

The conservation history matters as much as the geography. Mazunte, now the quietest town on the stretch, was once a place where turtle meat and shell were part of the local catch. When the federal government banned sea turtle exploitation in 1990, the town had to reinvent itself — and it did, around the turtles themselves. The result is the Centro Mexicano de la Tortuga (the Mexican Turtle Center), a research and education center that draws visitors and funds the work, and a network of community turtle camps along the whole shore. You can read about how that came together in our guide to Mazunte's turtle sanctuary and bioluminescence.

A coast that still has room for a turtle to nest is a coast that has not been overbuilt — one of the reasons we do not expect the Oaxaca shore to go the way of Tulum.

The turtles

The species and how to tell them apart

Five sea turtle species live in the waters off Oaxaca, and each one nests here in some measure. Only one of them — the olive ridley — is the reason people talk about this coast in the same breath as anywhere else in the world. Knowing which is which makes the beach far more interesting.

• Olive ridley (tortuga golfina) — the one you will actually see in numbers. A small, mostly grey-green turtle, roughly 70 centimeters from shell to tail, with an olive carapace and a near-perfect circle when seen from above. This is the species that forms arribadas.
• Green turtle (tortuga verde) — larger, with a more oval shell and a head that looks small for its body. Despite the name, its shell is usually brown or olive; the green is the fat beneath. Nests solitarily, and like the golfina, occasionally joins a shared beach.
• Hawksbill (tortuga carey) — the one with the raptor-like beak and a shell of overlapping, saw-toothed scutes. Critically endangered and solitary, it shows up rarely on this coast. Its shell was once turned into combs and jewelry; buying those is illegal.
• Leatherback (tortuga laúd) — the giant of the group. It can reach a meter and a half and over 400 kilograms, and it has no hard shell at all, but a leathery, ridged back. It nests individually, usually at night, and it is a rare, unforgettable sight.
• Loggerhead (tortuga caguama) — a big-headed, reddish-brown turtle, more common in the Atlantic but present in Pacific waters. You are unlikely to see one on the beach; if you are lucky you will see one offshore.

If you see a single sea turtle on the beach at night, odds are it is a green, a leatherback, or a hawksbill going about it alone. If you see tens or hundreds, it is an arribada of golfinas — and that is its own thing.

The calendar

When each species nests — the calendar

Here is the honest part: no one can hand you a precise date for a sea-turtle arrival, because turtles do not keep a calendar. They follow the water temperature and the moon. What we can give you is the reliable window — the months when nesting is common, the months when it is rare, and the species you are most likely to see. Treat the table below as a guide for planning, not as a guarantee.

Species	Jan–Mar	Apr–Jun	Jul–Sep	Oct–Dec	What you'll typically see
Olive ridley (golfina)	Sporadic	Sporadic	Peak	Peak to tapering	Arribadas on La Escobilla and nearby beaches; the main show.
Green (verde)	Occasional	Rising	Peak	Occasional	Single females emerging on quiet stretches of sand.
Leatherback (laúd)	Occasional	Rare	Rare	Sporadic	A rare lone giant, usually at night; treat it as a bonus, not a plan.
Hawksbill (carey)	Rare	Rare	Sporadic	Rare	Very uncommon; if you see one, consider yourself lucky.
Loggerhead (caguama)	Rare	Rare	Rare	Rare	Unlikely on the beach; mostly a sighting offshore.

In practice, the strongest time for sea turtle nesting season in Oaxaca is the rainy season, roughly August to November, when the water is warm and the golfinas arrive in the biggest waves. The full moon and the new moon both tend to draw them, though it is the water that sets the timing, not the phase. The rest of the year there is always a chance — just a lower one — which is why the camps work through the year rather than for a few months.

The arribada

The arribada: what an arribada actually is

The Spanish word arribada means "arrival," and it describes a phenomenon you have to see to believe. Over a few consecutive nights, anywhere from hundreds to tens of thousands of female olive ridleys come ashore together, dig their nests, lay their eggs, and slide back into the surf. It is not a single night; it is a pulse. A big arribada can run for several nights and cover a beach so thoroughly that the sand looks churned and pockmarked under torchlight the following morning. La Escobilla hosts some of the largest arribadas in the world.

What makes an arribada special is not just the number. It is the synchronization. The females gather offshore, wait for the tide and the dark, and then move as one. Scientists do not fully agree on why they synchronize this way — the prevailing idea is that it overwhelms predators and protects the eggs, but the mood is best described as a kind of collective decision no one can predict. The camp that guards the beach cannot tell you which night will be an arribada. They can tell you when one is happening because the beach suddenly has turtles on it, and everyone scrambles.

An arribada has no phone. You can wait on the sand for a night and see nothing, and then walk out two nights later and the beach is covered.

That is the honest truth of it. If you want to see one, the best you can do is go in the peak months, stay for a few nights, and go with a group that has eyes on the beach — a camp or a licensed guide rather than a loose crowd. It is worth the patience.

The releases

Release events: how to see one, done right

Most visitors who say they "went to see the turtles" actually mean one thing: they went to a liberación — a hatchling release. It is easier to plan for than an arribada, and for good reason. The camps gather hatchlings as they emerge, keep them in protected containers, and release them at dusk in a way that gives them a fair run at the water. It is a justly popular thing to watch. It is also very easy to get wrong, and wrong is not just a disappointment — it costs turtle lives.

A well-run release has a rhythm. You arrive before dusk. The guide explains the species, the journey, and the odds — most hatchlings do not survive their first night, which is part of why the human hand helps. You wait for the signal, and then the hatchlings are placed on the sand and, without being touched, walk toward the water while you stay back and low. This is the important part: do not pick up a hatchling. They are fragile, and the ones handled by many hands are the ones that do not make it. The guide or camp volunteer sets them down; everyone else watches.

Two practical notes. First, pick a release run by a campamento tortuguero or an authorized center, not by a stranger collecting cash on the beach. Turtles are protected, and the good operations use their fees to fund the work. Second, skip the flashlight and the camera flash. Either one disorients a hatchling and can send it walking inland instead of toward the sea. And never touch a nesting female — she has laid her eggs and she will do what she needs to do.

The towns

Where to go by town

The coast is short enough to treat as a single turtle region, but the towns each have their own flavor — and their own access.

• Mazunte — the natural base. The Mexican Turtle Center is here, the camps are close by, and the beach is small and calm. This is where most turtle-focused visitors stay.
• La Escobilla — the arribada beach itself, and the most important conservation site on the coast. It is protected, so you do not simply wander in. You go with an authorized camp or guide, which is both a rule and a reassurance.
• San Agustinillo and Zipolite — right next door to Mazunte, good for walk-in releases from the local camps and for separating your turtle mornings from your beach afternoons.
• Puerto Escondido — the bigger town, with more accommodation and boat trips that sometimes spot turtles and dolphins offshore. The nesting beaches are a short drive away.
• Huatulco — at the far end, quieter for turtles but within reach of the beaches along the bay. Details on the ecology of the whole stretch are in our guide to wildlife and environment on the Oaxaca coast.

If an arribada is the goal, La Escobilla is the place — but understand that you buy into patience, not a schedule. If a release is the goal, almost any town with a camp will do, and Mazunte and San Agustinillo are the easiest bets. For a deeper look at La Escobilla and its surroundings, see our guide to La Escobilla.

The rules

What to know before you go — rules and respect

Sea turtles are federally protected in Mexico, and the rules exist for a reason: the species here are some of the most endangered on the planet, and a beach full of well-meaning onlookers can undo an evening of conservation work in minutes. Here is how to do it right.

• Go with a guide, a camp, or an authorized center. It is the difference between a respectful visit and an intrusion, and it is usually the only legal way onto a protected beach.
• Never touch a nesting female or a hatchling. If you want a photo, take it from a distance and without a flash. Bright light and human scent are disorienting and can send a turtle back to the sea without laying — or a hatchling the wrong way.
• Wear dark clothes and go barefoot or quiet. Turtles have evolved for dark, undisturbed beaches. Footlights, white socks, and yelling are all subtle ways to ruin the night.
• Approach from behind, and stay low. A nesting female's head is her lookout. Let the guide position you where you will not block her or startle her.
• Do not walk where turtles have dug. A safe hatchery protects the eggs from dogs, crabs, and people. Crushing a nest is a silent, lasting harm.
• Never buy tortoiseshell or turtle products. It is illegal, and it funds the poaching that the whole protected-beach system is designed to stop.

Respect is not a formality here; it is what keeps the turtles coming back. Watch the beach the way the camps ask you to, and you will be part of the reason it still happens.