Green Turtle (Chelonia mydas)

Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help



The green turtle is the largest hard-shelled sea turtle, it has a carapace (shell) up to 1.4 m in length and can weigh a total of 180 kg. The green turtles smooth carapace, small rounded head and four pairs of scales (costal scutes) is what distinguishes it from other sea turtles. The shell of this species varies in colour from olive to brown, grey and black with swirls and irregular patterns.

Recorded distribution in Britain and Ireland

Records from south and west coasts of England and north-west Scotland and Shetland.

Global distribution



Adults inhabit shallow tropical feeding grounds that are often seagrass meadows, migrating from these areas to their nesting beaches not in the UK.

Depth range


Identifying features

  • Shell varies from olive to brown, grey and black with swirls and irregular patterns.
  • Up to 140 cm in length and weigh up to 180 kg.
  • The small rounded head has four pairs of scales (costal scutes).

Additional information

The green turtle is protected form international trade by its listing on Appendix I of the Convention on International Trade in Endangered Species (CITES). Populations of green turtles are in serious decline due to a number of factors. These include loss of nesting habitats, destruction of nests by poachers, propeller wounds, interaction with commercial fisheries and ingestion of marine debris, demand for their eggs and meat for human consumption.


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  4. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  5. Meylan, A., 1995. Estimation of population size in sea turtles. In: Conservation & Biology of sea turtles. Washington & London: Smithsonian Institution Press.

  6. National Research Council, 1990. Decline in Sea Turtles: Causes and Prevention. Washington, D.C: National Academy Press.

  7. Penhallurick, R.D., 1990. Turtles off Cornwall, the Isles of Scilly and Devonshire. Truro: Dyllansow Pengwella.

  8. Seminoff, JA., 2004. Chelonia mydas. In: IUCN 2006. 2006 IUCN Red List of Threatened Species.,


  1. Marine Environmental Monitoring, 2018. Marine Turtles. Occurrence dataset: accessed via on 2018-10-01.

  2. NBN (National Biodiversity Network) Atlas. Available from:

  3. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2024-05-25


This review can be cited as:

Harris, R. 2008. Chelonia mydas Green Turtle. In Tyler-Walters H. and Hiscock K. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 25-05-2024]. Available from:

Last Updated: 03/07/2008