The smallest of the sea turtles, olive-grey with a rounded shell, met in open water more often than on a reef.
Shell 61 to 72 cm and rarely over 50 kg, which makes it the smallest sea turtle apart from Kemp’s ridley. The shell is heart-shaped, rounded and olive to grey, and fairly high for its size. The head is triangular with concave sides.
The diagnostic is the scute count and it is unusual: five to nine costal scutes on each side, and the count is often different on the left and the right. No other sea turtle does that. The green turtle has exactly four pairs. Kemp’s ridley shares the general shape but is grey-olive and restricted to the Gulf of Mexico and the northwest Atlantic, so the two do not meet anywhere on this site.
Divers usually see it in blue water at or near the surface, often floating, on the way out to or back from a pinnacle. It is far less reef-associated than a green or a hawksbill. It eats jellyfish, salps, crabs, molluscs, tunicates and algae, mostly within 15 km of shore in 22 to 55 m, though satellite tracks show long periods far offshore and dives to about 200 m.
The species is defined by the arribada: thousands of females come ashore on one beach over a few nights, packed so densely that they dig up each other’s clutches. The main beaches are in Costa Rica, Mexico and Odisha in India. It is the most abundant sea turtle and is still listed as vulnerable, because Pacific nesting numbers fell by about a third in a single generation. The Galapagos and Revillagigedo records are sound; the evidence for Cocos is thin, and it should not be treated as a reliable sighting there.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.