There are actually 31 different types of sea snake and here on Koh Tao we only get the Banded Sea Snake or otherwise called Banded Sea Krait - Laticauda colubrine.
The snake is blue or blue-grey with 20-65 black bands and a yellow or cream colour underside on a cylindrical shaped body. The snout, upper lips and a bar above the eye are yellow and the tail is oar liked and provides propulsion.
The males can grow up to 75cm long and the females 128cm long. They are a unique from the majority of sea snakes as their courtship, mating and laying of their eggs takes place on land. Their food of choice is eels and small fish and they use their venom to paralyse their prey.
All sea snakes are dangerous to humans as they have such highly toxic venom and carry enough of it to kill approximately three adults.
After being bitten, side effects generally do not appear for 20-30 minutes, at which point severe pain is experienced in the affected limb. droopy eyelids, respiratory weakness and muscle pain can occur. You should apply a broad ligature between the injury and the body and wash the wound, CPR may be necessary. Medical assistance should be sought as soon as possible.
However the Banded Sea Snake is generally a pretty shy and docile creature that is not aggressive by nature. Plus their fangs are really tiny, only 2-4mm in length so would have trouble penetrating a wetsuit.
It is a cool sight to watch the sea snake slowly swim around the reef, or if you’re lucky enough to see them going up to the surface for air and you can often get some good photos of them.