What to do if you get stung by jellyfish or sea lice while swimming in Nha Trang?

Small jellyfish are more common. In September 2026 a participant compared their sting to touching a nettle: redness and irritation last about half an hour and then disappear without a trace. They added that plankton itself does not sting.

Tiny jellyfish larvae, according to reports from August–September 2026, sting tolerably, but sometimes quite strongly on sensitive skin — for example, the inner elbow. One traveler noticed they appeared only at high tide.

In July 2026 a participant wrote that marks from the tiny creatures in the water look very unpleasant even though they do not really bite, whereas a jellyfish stung a young woman much more seriously.

In July 2026 a participant posted general first-aid tips generated by an AI chatbot — not medical advice from a doctor. They said to take off your swimsuit as soon as possible and rinse the skin with seawater or saline rather than fresh water; apply table vinegar to the area; remove any remnants with tweezers or a plastic card without rubbing; and apply a cold compress. Before relying on such tips, especially for children, check with a doctor or pharmacist.

The same tips posted in July 2026 advised seeing a doctor immediately in case of severe swelling, fever, nausea, vomiting (more common in children) or signs of infection, naming Khanh Hoa Provincial General Hospital as an example of a hospital in Nha Trang. They also noted that a swimsuit should be washed before wearing it again after such a rash.

In one group's experience in July 2026, after a jellyfish sting they were given lime and told not to wash the area under running water; they also took an antihistamine, which helped. The same traveler wrote that when plankton stung them, there were no after-effects.

Jellyfish stings should not be underestimated: in July 2026 a traveler warned that very venomous jellyfish occur in Nha Trang and can leave serious burns on adults — his wife's burn took about three months to heal.