Symptoms to watch for, when to see a doctor, and how to report illness to the Department of Health.
This guide is for general informational purposes only. If you are experiencing symptoms after swimming, see a doctor or visit urgent care immediately. Tell them you swam in the ocean in Hawaiʻi.
Enterococcus bacteria are the primary indicator organism that Hawaiʻi's Department of Health tests for at beaches. When levels exceed 130 CFU/100mL, advisories are issued. But even at levels below this threshold, some swimmers get sick — especially children, elderly visitors, and those with compromised immune systems.
Enterococcus itself may or may not cause illness directly. Its significance is as an indicator: when Enterococcus levels are high, other dangerous pathogens — including viruses, parasites, and more harmful bacteria — are also likely present in the water from the same contamination sources.
Most cases resolve on their own within 1–3 days. Stay hydrated. See a doctor if symptoms persist beyond 48 hours or include bloody stool.
Staphylococcus aureus, including the antibiotic-resistant strain MRSA, has been detected in Hawaiʻi's coastal waters, particularly near areas with sewage or cesspool contamination. Hawaiʻi has some of the highest MRSA rates in the nation. These bacteria enter through broken skin — cuts, scrapes, reef cuts, or even minor abrasions you might not notice.
Important: MRSA requires specific antibiotics. Standard antibiotics will not work. Tell your doctor you were in ocean water in Hawaiʻi so they can test for resistance.
Leptospirosis is primarily a freshwater risk (streams, waterfalls, flooded areas), but can be relevant near stream mouths where fresh and salt water mix. Hawaiʻi accounts for roughly 50% of all U.S. leptospirosis cases. This infection can be fatal if untreated.
If you swam in freshwater in Hawaiʻi and develop these symptoms, seek emergency care immediately and tell the doctor about your exposure.
If you get sick after swimming in Hawaiʻi, consider reporting it to the Department of Health Clean Water Branch. Your report helps DOH track contamination patterns and may trigger additional testing at the beach where you swam. This data directly protects other swimmers.
If you need medical care during your trip, every major island has hospitals and urgent care facilities. Your hotel concierge can help you find the nearest option. Many resorts also have on-call physicians.
Recovering from illness or avoiding the water? Top-rated land-based activities across Hawaiʻi.
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Safe to Swim Hawaii is an independent passion project — not affiliated with the Hawaii Department of Health or any government agency. This page provides general health information and is not medical advice.
Always verify current water quality with the Hawaii DOH Clean Water Branch before entering the water.
When in doubt, don't go out. 🤙