4 islands compared with data-backed recommendations
| Island | Score | Top Beach |
|---|---|---|
| Oʻahu | 5/10 |
— |
| Maui | 8/10 |
Kapalua Bay |
| Big Island | 9/10 |
Kua Bay |
| Kauaʻi | 7/10 |
Poipu Beach |
Top beach: Kua Bay
Why: Kona coast has consistently clean water due to volcanic filtration and low runoff
Caveat: Not all Big Island beaches are clean — Kahaluʻu has the worst bacteria in the state
Top beach: Kapalua Bay
South and west Maui beaches consistently pass water quality tests
Urban runoff, Ala Wai Canal contamination, multiple chronic advisory beaches
Based on our analysis, Big Island is the top pick for clean water in Hawaii. Kona coast has consistently clean water due to volcanic filtration and low runoff. The top beach for this is Kua Bay.
Big Island is generally good for clean water throughout the year, though conditions vary by season. Not all Big Island beaches are clean — Kahaluʻu has the worst bacteria in the state
While all four main islands offer some version of this experience, the quality varies significantly. Oʻahu is the weakest option because: Urban runoff, Ala Wai Canal contamination, multiple chronic advisory beaches
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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.
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.
When in doubt, donʻt go out. 🤙