Water quality status and bacteria risk rating
📍 West Oʻahu, Keawaʻula — End of Farrington Highway
Yokohama Bay (Keawaʻula) has excellent water quality thanks to its remote, undeveloped location at the very end of Farrington Highway on Oʻahu's west coast. There is virtually no nearby development, no stream runoff, and the powerful open ocean provides exceptional flushing.
The primary danger at Yokohama Bay is not bacteria but strong currents and powerful shorebreak. This is not a monitored beach — there are no lifeguards, and rescue response time is significantly longer due to the remote location. The steep sandy beach creates dangerous shore break and rip currents, especially during winter swells.
Based on: Remote location, no development or stream input, excellent ocean flushing, no regular DOH monitoring
The Department of Health recommends staying out of the ocean for at least 72 hours after heavy rain. Yokohama Bay's remote location means minimal runoff risk, but heavy rains can wash debris from the surrounding hillsides into nearshore waters. Always check the water visually before entering.
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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 or any government agency. 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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