Box Jellyfish Thailand, Malaysia, Philippines & The Region

So, how safe is Koh Samui? There's been plenty of confusion and panic. Is it OK to swim? How many of these 'killer jellyfish' are there? Where are they? What do they look like? How big is the risk? What do I do if I get stung? Here is the original guide , followed by a September 2025 update. The risk remains.

  Zoe Cahill, a 23-year old Australian, was 50-metres offshore at Zen Beach on Koh Phangan in October 2023 when she swam into a box jellyfish and received excruciating life-threatening stings.  Alone in shock and agony, crying and screaming, Zoe summoned all of her courage and strength and somehow managed to get back to land, collapsed and critically began to turn blue.  Desperate first-responders frantically doused her in litres of vinegar while a nurse performed CPR and, after restoring vital signs, she was rushed to the local hospital.  An emergency speed-boat transported Zoe to Koh Samui where with extreme sting damage to limbs and torso she remained in a hospital bed for a month. Zoe's story as covered in mainstream media including Australia's 9 News and  related to thousands of her  @zoe_cahill  Instagram followers on  social media is another cautionary tale of survival with box jellyfish in South-East Asia...

  Thailand may not have got everything perfect in its fight against box jellyfish, but it has got a lot right and been nothing short of proactive and persistent. A far cry from a number of its neighbours. Box jellyfish stings still occur in Thailand as do the occasional fatalities. No surprise here with so many beaches being their natural habitat. However, it could be much worse. In 2015, for example, popular Koh Samui was in a world of pain with a series of widely-publicised box jellyfish deaths threatening the island's rich tourism industry. Instead of burying their heads in the sand as others have, the Thais took the initiative and created a prevention and treatment program involving experts, government officials, hospitals and locals. It worked. And it still works. There are now many examples on this blog of how the Thais have achieved such impressive results. There are also some examples of what they have got wrong, though they are far outweighed by the successe...

  A nine-year old boy has died after being stung by a box jellyfish at Haad Rin on the island of Koh Phangan in Thailand. The tragic news filtered through after weeks of warnings from authorities about the heightened seasonal risk to  swimmers  in the region including Koh Samui, while treating a number of victims for box jellyfish stings. The boy who was with his family, Israeli nationals that have reportedly been living on the island for several years, was swimming outside of a nearby protective jellyfish prevention net on the evening of Saturday 28 August, 2021 when the incident occurred. Matichon, a major Thai-language national daily newspaper, reported that efforts were made on the scene to administer proper first aid, including vinegar, and to revive the boy who was rushed to Phangan International Hospital. Director-General of the Department of Marine and Coastal Resources,  Mr. Sophon Thongdee,  was quoted in Matichon saying, "B ox jellyfish...

Serious box jellyfish stings on Koh Samui as reported in the French language Le Petit Journal, 21 November 2019. Of the 3 children stung, the most serious was that of a 12-year old boy who required CPR on his way to the local hospital where he was placed in a coma and flown by private jet to Bangkok.  Details follow in French and English as well as a Facebook link to the public appeal of the children's mother. FURTHER READING LINKS: Sting victim's mother's Facebook appeal Le Petit Journal online article Trois enfants français survivent à des cuboméduses à Koh Samui Un jeune français de douze ans survit à une piqûre de cuboméduse ou méduse-boîte à Koh Samui après avoir fait un arrêt cardiaque et été plongé dans le coma pendant deux jours. Deux autres jeunes filles, plus légèrement touchées sont hors de danger.  Cela devait être la dernière journée à la plage de Lamai à Koh Samui avant de rentrer en France pour cette famille originaire du Var. Le mardi...

Fodor's Travel website published an article by Jacob Dean on 16 July, 2019 that brings the issue of box jellyfish in Thailand into the mainstream.  Social media posts, blogs such as this and local media reacting to sting events or official warnings have long been the major source of current and topical information on Thailand's box jellyfish problem. Fodor's is now front and centre. This news article is for the most part accurate, though there are several factual errors to note.  Firstly, this is not the 'Australian box jellyfish'. It is the Thai box jellyfish otherwise known as Chironex Indrasaksajae.  It's not an illegal alien from Oz, Thailand owns it! The 'general lack of eduction' and 'various conflicts of interests from stakeholders' the author references from 2016 has greatly improved, though is still far from perfect. A number of fatalities had occurred at this time and Thailand has officially upped the ante in the 3 years sin...

As reported on the website of Thailand's Bureau of Epidemiology, a Memorandum of Understanding (MoU) was signed at a conference in Bangkok bringing various government departments, authorities, universities, interested groups and coastal communities together in the fight against the threat of box jellyfish. The MoU is another major step forward officially creating closer, long-term co-operation and collaboration from the highest level of government to the beachside officials and operators who manage the risk. Following is an edited transcript from the website:    The Department of Disease Control, Ministry of Public Health are moving forward to develop our epidemiological network and create knowledge of the prevention of injury and death from venomous jellyfish in Thai sea waters. Today (21 May, 2019) at Centra Hotel by Centara Government Center and Convention Center, Chaengwattana, Bangkok, Dr. Suwanchai Wattana Yingcharoenchai, Director-General of the Department ...

A selection of this blog's images from South-East Asia including box jellyfish, sting victims and locations. Thailand's Chironex indrasaksajiae S ucharitakul   sp. Langkawi, Malaysia Morbakka, Koh Tao, Thailand Koh Mak, Thailand Phuket, Thailand Koh Phangan, Thailand Koh Samui, Thailand Koh Lanta, Thailand Koh Samui, Thailand Philippines Thailand Training session, Thailand First Aid Vinegar Pole, Thailand Jellyfish prevention net, Thailand Koh Samui, Thailand All photo credits duly acknowledged where possible throughout the blog.

Tracking Thailand's progress over a 10-year period since the Kingdom officially acknowledged their box jellyfish problem could be compared to a trek to Mae Hong Son. It's been a slow ascent. They've been plenty of challenges, obstacles, slips and step-by-step successes. And after climbing hill after hill it is clear that there's still a long way to go.

Jellyfish warning for travellers swimming in Thailand

Th ai authorities have installed the first of a series of prototype box jellyfish prevention nets in some of the country's sting hotspots.

There has been a spike in reports of jellyfish stings on Koh Samui recently. Generally around Lamai Beach. Most it appears can be attributed to single and multiple-tentacle box jellyfish. In August, 2016 alone there were 17 people with serious stings admitted to hospital for treatment. Fortunately there have been no reported deaths.