Green Turtle
Scientific name Chelonia mydas
The Green Turtle is one of the most iconic and beloved marine animals you can encounter around Koh Tao. Recognisable by its smooth, oval-shaped shell and relatively small head, this gentle ocean giant can grow over 1 metre in length.
Despite the name, the shell is usually olive-brown rather than bright green. The “green” actually refers to the colour of the fat beneath its shell, which is influenced by its largely herbivorous diet.
Around Koh Tao, Green Turtles are occasional but special sightings. They are most often seen grazing on seagrass beds or algae growing on reef surfaces between 3–20 metres. Sometimes they rest quietly beneath coral overhangs or cruise calmly through shallow bays.
Green Turtles are slow, graceful swimmers but capable of powerful bursts of speed when needed. They must surface regularly to breathe, though they can remain underwater for extended periods while resting.
They are classified as endangered due to habitat loss, fishing pressure and marine pollution, making every respectful encounter an important reminder of ocean conservation.
Find Green Turtle at...
Divemaster's tip
If you see a turtle, remain calm and neutrally buoyant. Never chase, block its path or swim above it.
Give plenty of space — especially if it is feeding or surfacing to breathe. Calm observation often allows for longer, more natural encounters.
What do they eat?
Adult Green Turtles feed primarily on seagrass and algae. Juveniles may have a more varied diet including small invertebrates.
By grazing algae, they help prevent overgrowth on reefs and maintain healthy seagrass ecosystems around Koh Tao.
