There are a number of species of jellyfish that can be found in Thai waters. Most of the jellyfish seen in Thailand are relatively harmless, but there is one species in particular which can cause real problems; the Box Jellyfish. There is also another marine creature that can cause painful stings, the Portuguese Man-of-War (sometimes called Blue Bottles). Although the Portuguese Man-of-War is not technically a jellyfish it has the appearance of one and can cause agonising stings. Of the two species, the Box Jellyfish is more common in Thailand. The Portuguese Man-of-War is not native to Thai waters, but can appear depending on weather conditions. During the monsoon season in Thailand, changes in wind direction and storms can bring these marine creatures closer to the shore where they pose a risk to swimmers and snorkelers. Dead jellyfish can also be washed up on beaches and shouldn’t be touched because they can still sting.
In areas where it is known there is a risk of sting from jellyfish or other marine creatures, warning signs in Thai and English are put in place on beaches. First aid points are also set up on beaches with an increase in lifeguard patrols. Hotels in the affected areas should issue notices to guests. Whatever the time of year, visitors are asked to be vigilant when swimming or snorkelling and heed any warning notices or flags. Stings from Box Jellyfish can be fatal.
Where and when is there a risk of jellyfish stings in Thailand?
Most reports of Box Jellyfish in Thailand have come from the waters off Krabi, Phuket, Ko Lanta and Phi Phi. There have also been cases of Box Jellyfish stings reported on Ko Samui and Ko Pha Ngan. There is an added risk in swimming at night with jellyfish more difficult to spot. Jellyfish tend to be more of an issue in the wet season with changes in wind direction and seasonal storms bringing some marine creatures closer to shore. It’s not unusual to see jellyfish washed up on southern Thai beaches after storms, but they can still posses the ability to sting so don’t touch them.
Advice from marine biologists
The Tourism Authority of Thailand (TAT) advises tourists to refrain from swimming and snorkelling in areas where warning signs are in place. Tourists are also asked to be extra careful at times when jellyfish and other stingers are known to be present in Thai waters. This is the advice from TAT issued via a marine biologist:
- Look all around when in the water and try to swim with a partner. A sting can sometimes immobilise a person making it difficult to swim to shore.
- Consider wearing protective swimwear like a rash guard or swimming shoes.
- Beware of seemingly dead jellyfish on the beach. If they were recently beached they can still give a painful sting.
If you or any other bathers make contact with the stingers of a jellyfish, your first priority is to stay calm. Make sure somebody calls immediately for medical help and follow the first aid advice below (issued by Thailand’s health authorities).