Sea Snake Bite

Reviewed on 10/11/2021

Sea Snake Bite Facts

Sea snakes
A bite from a sea snake does not cause pain initially.
  • Sea snakes are usually 3-5 feet long (some can grow to 9 feet) with flat tails and scales. There are at least 52 species known and all of them are venomous. They are found in tropical and warm waters of the Pacific and Indian Oceans. There are no sea snakes in the Atlantic Ocean or the Caribbean Sea. Although they evolved from terrestrial ancestors the vast majority cannot move on land.
  • They can move both forward and backward in the water with equal speed. They can dive as deep as 328 feet and stay underwater for two hours. It is an air breather and must come to the surface to survive. A sea snake has scales whereas eels do not.
  • Sea snakes are usually not aggressive unless provoked or cornered. Although they are highly venomous, only some bites result in significant symptoms of envenomation.
  • The venom is injected by fangs. Most specy's fangs are not long enough to penetrate through a wetsuit. The venom is very potent and toxic.
  • Bites typically occur when fishermen are removing the snakes from fishing nets or if the snake is stepped on while wading in the water.
  • Sea snakes can migrate into rivers from coastal waters and estuary settings (up to 3 miles).

What are the symptoms of a sea snake bite?

  • A bite from a sea snake does not cause pain initially.
  • The site of the bite may show only a small pinprick where the bite occurred without pain. Sea snakes bites could show anywhere from 1 to up to 20 "fang" marks.
  • The site of the bite rarely shows a reaction. The person who was bitten by the sea snake won't usually see redness, bruising, or other signs at the location of the bite, even if venom was injected.
  • Attempts should be made to capture or kill the snake for identification by an expert.

As sea snake venoms are neurotoxins, the typical symptoms of sea snake bites begin within three hours and include:

  • Painful muscles
  • Paralysis (inability to move) legs
  • Joint aches (arthralgias)
  • Blurry vision
  • "Thick tongue" with difficulty swallowing or speaking
  • Excessive saliva production
  • Vomiting
  • Droopy eyelids (ptosis)

If no symptoms develop within eight hours then venom injection is very unlikely.

Sea Snake Bite First Aid Treatment

  • The amount of venom injected (if any) cannot be predicted, and therefore, any suspected bite by a sea snake should be considered potentially life-threatening and the person bitten should seek immediate medical attention.
  • Use the pressure immobilization technique for a sea snake bite.
    • Use an elastic bandage (similar to an ACE bandage) to wrap the limb starting at the distal end (fingers or toes) and wrap toward the body. It should be tight but the fingers and toes should remain pink so that the circulation is not cut off (this is not supposed to be a tourniquet)
    • The extremity should also be immobilized with a splint or stick of some sort to prevent it from bending at the joints.
    • The elastic bandage should be removed for 90 seconds every 10 minutes and then reapplied for the first 4 to 6 hours. (Hopefully, medical care can be received within this time period.)
    • If more than 30 minutes pass after the bite the pressure immobilization technique is not likely to be helpful.
  • Keep the victim calm, warm, and still, and as comfortable as possible.
  • There is no benefit to suctioning or cutting the bite area to "suck the venom out."
  • The overall death rate is 3% for victims bitten by sea snakes. In cases where there is "severe" envenomation, the rate is 25%.
  • There is anti-venom available and should be started as soon as possible when a health care professional determines it is needed. It has been shown to be most effective if given within 8 hours of the sea snake bite.

When to Seek Medical Assistance for a Sea Snake Bite

Seek immediate medical care regardless of the circumstances due to the inability to predict if a true bite occurred.

Sea Snake Pictures

Sea snake.
Sea snake.

Sea snake.
Sea snake.

Reviewed on 10/11/2021
Medically reviewed by Avrom Simon, MD; Board Certified Preventative Medicine with Subspecialty in Occupational Medicine


Auerbach, P. Wilderness Medicine. Chapter 81. 6th ed. United States: Mosby, 2011.