Jellyfish Sting in Hawaiʻi

Portuguese man-of-war guidance is the place where sources disagree most. Some University of Hawaiʻi research and Hawaiʻi public materials discuss vinegar and heat for Physalia stings; some emergency protocols and medical references still mention saltwater or seawater rinsing.

Because the guidance is mixed, Safe to Swim Hawaii does not recommend a treatment sequence. Alert a lifeguard or local first-aid provider if one is present, and seek urgent care for severe symptoms.

Myth: Urinate on the sting. This does not work and may make it worse by triggering more stinging cells.

Freshwater is commonly discouraged. Several medical references warn that freshwater can trigger undischarged stinging cells. Ask local first-aid personnel what to use for the species involved.

Myth: Scrape with sand. Rubbing sand on a sting can trigger remaining nematocysts and grind them deeper into the skin.

Ice versus heat depends on source. Some sources discuss heat; some sources discuss cold for pain relief. This site does not choose between them for you.

• Check the jellyfish calendar before visiting Oʻahu beaches
• Look for posted jellyfish warning signs at beach entrances
• Scan the shoreline and water for jellyfish before entering
• Wear a rash guard or full-coverage swimwear for added protection
• Avoid touching beached jellyfish or man-of-war — they can sting even when dead
• If jellyfish are spotted, alert lifeguards and other swimmers
• Ask lifeguards what first-aid supplies and local guidance apply at that beach