Sea snakes are capable of remaining submerged for up to 2 hours by decreasing its metabolic rate and developing an increased tolerance for low oxygen levels. After one breath at the surface, it can dive again. A sea snake also has valve-like flaps over its nostrils to stop water flowing into the lungs. The lungs of sea snakes are greatly enlarged, extending to the base of the tail enabling a large volume of oxygen to be stored in the lungs. Parts of the lung are believed to function as a hydrostatic organ regulating the snake's buoyancy.
Gaseous exchange occurs through both the lungs and the skin.
There are two methods of reproduction including - The sea snake may mate and lay their eggs onshore in crevices or caves. These eggs are capable of existing for long periods of time out of the water, or The sea snake may mate at sea and give birth to live young. The venom of a sea snake is approximately two to ten times as toxic as that of a cobra. However, due to poorly developed delivery apparatus, very little venom is actually delivered when the sea snake bites. Because of this, only about one quarter of people bitten by sea snakes ever show signs of poisoning.