Australia’s Great Animal Dives index

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MARINE TURTLES

Ancient mariners of the oceans!

SPECIES DETAILS

GREEN SEA TURLE
Scientific name:
Chelonia mydas
Habitat:
Coastal waters near seagrass beds & coral reefs
Population:
85,000 to 95,000 nesting females worldwide
Conservation status:
Vulnerable (Protected in Australia)
Australian distribution:
Tropical and sub-tropical waters, particularly the Great Barrier Reef & the northern coast

HAWKSBILL SEA TURTLE
Scientific name:
Eretmochelys imbricata
Habitat:
Coral reefs, rocky outcroppings & mangrove estuaries
Population:
57,000 to over 83,000 worldwide
Conservation status:
Critically Endangered (Protected in Australia)
Australian distribution:
Tropical coasts, from mid-western WA to QLD

LOGGERHEAD SEA TURTLE
Scientific name:
Dermochelys coriacea
Habitat:
Bays, coral reefs & estuaries
Population:
60,000 nesting females worldwide
Conservation status:
Endangered (Protected in Australia)
Australian distribution:
Coastal, tropical & subtropical waters along the eastern coast, particularly QLD & NSW

INFORMATION
Marine turtles can be found on every continent except Antarctica and have been around for over 100 million years, preceding mammals, birds, snakes and lizards.
Six of the world’s seven species of sea turtle can be found in Australian waters.
The most commonly encountered are green, hawksbill and loggerhead turtles, particularly around Cook Island just off the Gold Coast where the is a resident population of 300 to 400 turtles.
Australian nesting sites include Heron, Lady Elliot & Raine Islands in the Great Barrier Reef and Western Australia’s Kimberly region.
Raine Island is the world’s largest nesting rookery of endangered green sea turtles with an estimated 30,000 breeding females. Over 12 million eggs, in clutches of 60-150 eggs, are deposited in the Raine Island sand every year.
Nesting usually runs from November to March and hatchlings disappear into the open ocean reappearing two to ten years later. What happens during this time, referred to as the lost years, in unknown.
The sex of a turtle is determined by egg incubation temperature. All males at or below 26 Celsius (80°F), all females at or above 29 Celsius (84°F), some of both in between.
Typical incubation takes 100-150 days and only one in 1,000 hatchlings survive.
Sexual maturity takes between 11 and 40 years, depending on the species.
Adult turtles can live up 80 years, weigh over 50 kilograms (100 lbs) and reach over one metre (3’) in length.
Sea turtles are known to migrate thousands of kilometres.
Threats to sea turtles are, in the main, caused by humans and include bycatch, loss of habitat, coastal development and pollution, particularly plastics.
Global warming is also an existential threat, as nesting site temperature changes effect sex ratios of hatchlings.

Interactions with marine turtles can be seasonal, please check with the local dive services provider.

Special thanks to the Spirit of Freedom & Gold Coast Dive Adventures Teams.
Copyright © 2025 Steve Sinclair

DIVE DETAILS
Check with local dive services provider.

2026 GREAT AUSTRALIAN DIVE CHALLENGE
Dive Registration
To register this dive for validation, go to: www.50greatdives.com.
NOTE: Entrants should do this dive with one of the following preferred dive services.