Conservation director Suchart Rattanareangsri said: "It is highly unlikely that the crocodile was born and bred naturally in the waters of Phuket's west coast.
"The western coastal area of Phuket is not normally an environment that crocodiles come from.
"It most likely escaped from a nearby crocodile farm."
A drone captured the stunning panoramic shot which shows a crocodile swimming through the beautiful blue waters.
The perfect white sands and palm trees of Bang Tao Beach can be seen in the background.
Bang Tao is one of the longest beaches on the western coast of Phuket and is less developed than other areas of the island.
It is near the town of Cherng Talay, where locals make a living fishing, farming and rubber tapping as their ancestors did.
The area is also known for its crocodile farms where the animals are bred for their meat and leather.
Crocodiles have sometimes been seen around the island of Phra Thong, just north of Phuket.
But it is thought the one in the video escaped from a farm and managed to swim out to sea.
Although the farms breed freshwater crocodiles the animals are still able to swim in saltwater.
Phuket Provincial Fisheries Office are now investigating although they say they have not received any reports of crocodiles missing from farms.
They are now contacting local farms as well as going to Bang Tao to gather more information.
A spokeswoman said: "We cannot just guess where it came from, we have to investigate the issue."
