On a dark beach in Phang Nga, something ancient is happening. A shape the size of a small car heaves itself out of the Andaman Sea, dragging its enormous weight across the sand with slow, deliberate flippers. She has done this in roughly the same way for 100 million years — since the age of dinosaurs. She is a leatherback sea turtle, the largest turtle on Earth, and tonight she has come home to lay her eggs.
It is a scene that plays out on only a handful of beaches in all of Thailand, and almost all of them are here in Phang Nga and neighbouring Phuket. These two provinces are the only places in the country where leatherbacks — Dermochelys coriacea — still come ashore to nest [ref:1]. And in recent years, something quietly wonderful has been happening: they are coming back.
A giant among giants
Leatherbacks are not like other sea turtles. They are the largest of all seven sea turtle species, with adults routinely weighing between 300 and 640 kilograms and measuring up to 2.5 metres long [ref:2]. The biggest ever recorded washed ashore in Wales weighing 916 kilograms. Unlike their hard-shelled cousins, leatherbacks have no scutes or bony shell — their back is a layer of tough, rubbery skin stretched over seven longitudinal ridges, which is why they look like they are wearing ancient leather armour.
They are also the deepest-diving and most migratory of all turtles. Leatherbacks can dive to depths of roughly 1,200 metres — nearly 4,000 feet — and stay underwater for up to 85 minutes [ref:2]. Some swim more than 10,000 miles a year between feeding and nesting grounds. A leatherback tagged in the Pacific was tracked on a one-way journey of 13,000 miles [ref:3].
Their diet is almost entirely jellyfish, which they catch using pointed jaws and backward-pointing spines in their throats that stop the slippery prey from escaping [ref:2].
The Phang Nga nesting season
In Thailand, the leatherback nesting season traditionally ran from November to February. But since 2020, researchers from the Department of Marine and Coastal Resources have noticed something encouraging: the season has extended, now stretching from October all the way to July or August [ref:4].
The five main nesting beaches in Thailand tell you how important Phang Nga is. Three of them — Khuk Khak Beach, Bor Dan Beach, and Bang Kwan Beach — are all in this province. Only two are in Phuket [ref:4]. During the 2024–2025 nesting season, a single female nicknamed by locals laid multiple nests in the Ko Phra Thong area: one containing 127 eggs, another 124, a third 135, and a fourth 101 [ref:1]. Officials believe all four nests belonged to the same mother.
After a female lays her eggs, they incubate in the warm sand for about 55 to 60 days before hatching [ref:4]. A typical clutch contains around 100 eggs, and females may nest several times in a single season, returning every 8 to 12 days [ref:2].
Why every nest matters
The sobering context is that there are believed to be fewer than 10 nesting female leatherbacks remaining in all of Thailand [ref:1]. Three decades ago, the Andaman coast saw around 30 leatherback nests per year. By 2024, that number had dropped to about 10. Over the past seven years combined, only 69 nests have been observed [ref:1].
This makes every single nest precious. And it is why a network of people — from government scientists to village residents to hotel staff — has formed to protect them.
A community that watches the beach
At the heart of the effort is the Phuket Marine Biological Center (PMBC), led by senior marine biologist Hirun Kanghae. Since 2019, the centre has run a captive-rearing programme: weak hatchlings that would not survive on their own are nursed in ponds for over a year before release [ref:1]. Thailand is one of only five countries in the world that has successfully raised leatherback hatchlings to their first year [ref:1].
The centre also works with Upwell Turtles, a US-based non-profit. In April 2024, eleven captive-reared yearlings were fitted with tiny satellite tags and released into the Indian Ocean, each one transmitting data about where it goes and how it uses marine habitats [ref:1]. More tagged releases were planned.
But the science is only half the story. Since 2017, the PMBC has partnered with more than 50 coastal organisations — including beach hotels, community groups, and local volunteers — through a programme called Saving Sea Turtles [ref:1]. Hotels are asked to dim lights visible from nesting beaches, since bright lights can confuse both nesting mothers and new hatchlings trying to find the sea. Community members keep the beaches clean, because turtles avoid beaches that are noisy, brightly lit, or littered [ref:1].
It works. A female returned to Hat Mai Khao in Phuket to nest, and more hotels have joined the programme each year.
The long road from sand to sea
When the eggs hatch after those two months underground, the hatchlings face staggering odds. Under natural conditions, only about 0.1 to 0.2 percent of leatherback hatchlings survive to adulthood [ref:1]. Most are taken by predators, tides, or exhaustion before they ever reach deep water.
The ones that do make it enter a life of almost unimaginable scale — crossing ocean basins, diving deeper than submarines, outliving most animals on the planet. Leatherbacks reach sexual maturity at around 13 to 14 years of age [ref:4], and they return to the very beach where they were born to lay their own eggs, a behaviour called natal homing.
That instinct — to return — is what makes Phang Nga's beaches so important. A turtle hatching here tonight may, in 14 years, come back to this same stretch of sand. If the beach is dark and quiet and clean, she will stay.
How to be part of it
If you live on or visit the Andaman coast during nesting season (roughly October to August), there are simple things that help. Turn off or dim beach-facing lights at night. Keep beaches free of plastic and fishing line. Drive boats slowly near reef areas. And if you see tracks on the beach in the morning — wide, circling marks like a tractor tyre — report them to the Marine and Coastal Resources Office.
Every dark, quiet beach is an invitation. And somewhere out in the deep Indian Ocean, a giant older than the Himalayas is listening for it.
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