Sea Turtle Size: How Big Can Sea Turtles Get?

Sea Turtle Size

The information is current and up-to-date in accordance with the latest veterinarian research.

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The word “Sea turtle” creates the image of a species with a large body, streamlined shell, and flippers in my mind. The marine turtles live a mysterious life in the ocean. Hence, most of the life information of the sea turtles is unknown to us, but not their size and appearance.

The size of a sea turtle ranges between 20 to 108 inches, depending on the species. Kemp’s Ridley sea turtle is the smallest of marine turtles and grows between 20 to 29 inches. On the contrary, the leatherback sea turtle is the biggest among all turtle species, with a carapace length of 6 to 9 feet.

Do you know how big the other 5 sea turtle species can get? or why do marine turtles get so big? This article will answer all these questions.

How Big Do Sea Turtles Get?

Sea turtles have 7 species available in the world right now. Each species grows up gaining different sizes. I am including a chart indicating the average size of all sea turtle species.

Sea Turtle Size Chart:

Sea Turtle SpeciesAverage SizeAdditional Information
Leatherback Sea Turtle4 to 6.5 feetThe leatherback sea turtle is the largest among all the marine turtles. The species may grow up to 9 feet. The largest leatherback turtle ever recorded was 10 feet or 305 centimeters large.
Flatback Sea Turtle2.4 to 3.25 feetOn average, the flatback sea turtles grow around 3 feet. Usually, the female flatback sea turtles are larger than the males.
Green Sea Turtle3 to 5 feetA newborn green sea turtle is not more than 2 inches or 5 centimeters. The green sea turtle species is the largest among all the hard-shelled marine turtles.
Olive Ridley Sea Turtle2 to 2.5 feetThe Olive Ridley sea turtles are one of the smallest marine turtle species. The male and female Olive Ridleys grow about the same size. On average, each adult reaches over 2 feet.
Kemp Ridley Sea Turtle1.7 to 2.4 feetKemp Ridley sea turtle is the smallest marine turtle species. With a proper environment, the adult Kemp Ridley turtles reach about 2 feet in carapace length.
Loggerhead Sea Turtle2.5 to 3.6 feetThe average size of a loggerhead sea turtle is around 3 feet. The largest loggerhead marine turtle captured was around 7 feet (83.9 inches).
Hawksbill Sea turtle2 to 3.8 feetThe Hawksbill sea turtles are found in both short to medium sized. The male Hawksbill marine turtles are usually shorter than the females.

How Big Is A Full Grown Sea Turtle?

The average size range of a fully grown sea turtle lies between 2.5 to 4 feet. An adult marine turtle can be below the limit or as big as 6.5 feet depending on the species.

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Sea turtle species, such as Olive Ridley and Kemp Ridley, grow around 2 feet at their adult age. The Hawksbill sea turtle, loggerhead sea turtle, Green sea turtle, and flatback sea turtles get over 5 feet when they are fully grown.

Among all the marine species, the leatherback sea turtle is the largest. A fully grown leatherback has a carapace length of about 5 to 6.5 feet.

What Is The Largest Sea Turtle Ever Recorded?

The leatherback sea turtle is the biggest among all other marine turtles. The largest leatherback sea turtle ever observed and recorded was about 10 feet (120 inches).

Remember, the 10 feet was not the size of the leatherback turtle’s carapace. Instead, the length of the creature was measured from the tip of the beak to the endpoint of the tail.

The leatherback sea turtle is undoubtedly the largest marine turtle. At the same time, the species is also the biggest among all turtle species. The creature is also famous for being the fourth heaviest reptile in the world.

While other marine turtles hardly reach over 3 feet, the average size of the species is 4 to 6.5 feet. Some leatherback sea turtles may gain a carapace size of 9 feet when they are fully grown.

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Why Are Sea Turtles So Big?

Sea turtles are generally bigger than most other aquatic and semi-aquatic turtles. Experts suggest that the matured size of marine turtles actually helps them survive. How?

Well, you know the open ocean is full of uncertainty and predators. When the baby sea turtle leaves the shore and dives into the water, it is exposed to all kinds of dangers. For example, a mature shark grows to 28 to 25 feet. Devouring a sea turtle hatchling is a cup of tea for the tiger sharks.

Growing into a large size benefits the sea turtles to fight their opponents. With their streamlined body and large flippers, the marine turtles escape any danger within moments.

Again, the cold is terrible in the open sea. As an ectothermic species, sea turtles also depend on external heat.

However, these turtles are biologically programmed to generate a considerable amount of heat to survive until adapting to the conditions. Some experts believe a big body size and a thick layer of fat help marine turtles maintain a warm body temperature in the cold.

So, marine turtles have evolved in bulky size to cope with the environment. The large body of these turtles is their weapon of daily survival.

7 Popular Sea Turtle’s Lifespan & Size

Sea turtle Lifespan and Size

For a printable version of this amazing graphic, click here!

How Do Sea Turtles Grow And Develop?

Each marine turtle hatchling is born on the seashore. After coming out of the eggs, the babies go towards the sea and start their life.

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The sea turtles tend to live in deep water and far away from civilization. With sufficient food, the marine turtles grow into their desired size. These turtles return to their birthplace when they are adults and ready to breed.

We have little information about the years between birth and adulthood of the sea turtles. Hence, it is not possible to draw the exact growth chart of these turtles because of the lost years. But fortunately, we know the hatchling size of the sea turtles.

Here is a chart that includes the hatchling size of different sea turtle species:

Sea Turtle SpeciesSize Of The Hatchling
Leatherback Sea Turtle2 to 3 inches (5 to 8 centimeters)
Green Sea Turtles2 inches (5 centimeters)
Kemp Ridley Sea Turtle1.2 inches (3 centimeters)
Olive Ridley Sea Turtle1.5 inches (3.8 centimeters)
Hawksbill Sea Turtle2 to 3 inches (5 to 8 centimeters)
Flatback Sea Turtle2.4 inches (6.1 centimeters)

The baby sea turtles grow slowly into their full length. Most of the species stop growing once they gain sexual maturity, which at the age between 10 to 50 years.

If you want to learn more about a sea turtle’s life cycle and lifespan, go and check this article.


Sea turtles are bigger than most other turtle species. The larger body works in its favor to survive in the open ocean. Often the marine turtles are seen roaming around the beach. Try to rescue the pets or call the concerned authorities. In case you do not know how to identify a sea turtle, follow this article here.

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About Author

Muntaseer Rahman started keeping pet turtles back in 2013. He also owns the largest Turtle & Tortoise Facebook community in Bangladesh. These days he is mostly active on Facebook.


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