Millions of visitors travel to Thailand every year and many will head to Thailand’s beautiful beaches during their stay. The overwhelming majority of travellers will safely enjoy swimming in the warm tropical waters without any cause for concern. However, there are some important things to note, especially during the rainy season.
At a small number of beaches, there is a chance of jellyfish coming closer to shore. There are also some beaches where rip currents can develop. In cases where there is a potential hazard, signs will usually be in place and tourists should take notice of any warning flags.

(Photo: Roy Cavanagh)
Know the flag colours
- Red: The sea is dangerous. Do not go into the water.
- Yellow: Caution. Be extra careful if you go into the sea.
- Red and yellow flags: Lifeguards are on duty. Swim in the area between the flags.

(Photo: Roy Cavanagh)
Rip currents
Rip currents can be an issue at some beaches in Thailand. They usually occur during the rainy season, but beachgoers should pay attention to warning signs at any time of the year. Even where the waters may look benign, the red no swimming flags are in place for a reason. Locations where rip currents can be found include Phuket, Ko Samui and Ko Chang.

(Photo: Roy Cavanagh)
Not every Thai beach will have a lifeguard and ultimately swimmers are responsible for their own safety. Rip currents aren’t always easy to spot and may still occur on beaches where no warning flags are in place. Know in advance what to look for and how to get out of a rip current.

Ambulance
Dial 1669
Jellyfish
During Thailand’s rainy season, jellyfish and other stinging marine creatures can be blown closer to shore than usual. As with rip currents, warning signs are in place for a reason. Don’t enter the water where there are no swimming signs or warnings about jellyfish in the area. Beware too if you see any dead jellyfish on the beach; don’t touch them. They may still have the potential to sting.

(Photo: Shutterstock)
Several species of jellyfish found in Thai waters are harmless. However, dangerous box jellyfish are sometimes found in the sea in a number of locations including Hin and Cha Am, Ko Lanta, Ko Samui, Ko Pha Ngan, Ko Tao, Phi Phi Islands, and Phuket. In areas where jellyfish can be an issue, there should be first aid stations in place on the beach.
Advice from marine biologists:
- Be on the lookout for hazards in the water
- Try to swim with a partner
- Consider wearing protective swimwear
- If you are stung by a jellyfish try not to panic
- If someone is stung, take them to the beach and get them to lie still
- Do not wash or scrub the affected area with water or suntan creams
- Liberally apply vinegar (or seawater) to the affected area*
- Seek medical assistance
*At beach areas in Thailand, hotels, beach restaurants and diving outfits have been ordered by Thai authorities to keep bottles of vinegar easily accessible as part of their First Aid preparation.
For medical emergencies, call 1669
(nationwide ambulance service)
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