Which Beaches Are Cleanest?
Yes. Bacteria and pollutants in the water can enter your mouth, nose, and eyes while snorkeling. Poor visibility from runoff also makes snorkeling less enjoyable and can hide hazards. Choose beaches with low bacteria risk for the best experience.
Hanauma Bay (Oahu), Honolua Bay (Maui), Two Step (Big Island), and Tunnels Beach (Kauai) have both excellent reef systems and low bacteria risk. The dry-side beaches generally have cleaner snorkeling water.
Yes. Rain causes runoff that carries bacteria and sediment into the ocean, dramatically reducing visibility and increasing health risk. Wait at least 72 hours after heavy rain and until the water clears before snorkeling.
The Hawaii Department of Health recommends staying out of the ocean for at least 72 hours after heavy rain, even if the water looks clear. Bacteria and pollutants from runoff can linger in the water longer than the brown color does.
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⚠️ Important Disclaimer
Safe to Swim Hawaii is an independent passion project — it is not affiliated with the Hawaii Department of Health, any entity mentioned on this page, or any government agency or hotel brand. Water quality ratings on this site are estimates based on publicly available testing data and geographic analysis. They are not real-time measurements and may not reflect current conditions. “No DOH Alerts” means no advisory is currently posted — it does not mean the water was tested and found safe. DOH only monitors a fraction of Hawaii’s beaches, and some areas have no regular testing at all.
Always verify current water quality conditions with the Hawaii Department of Health Clean Water Branch before entering the water. This site is for informational purposes only and should not be the sole basis for any swimming decisions.
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When in doubt, don’t go out. 🤙