The smaller bay west of Haleʻiwa Beach Park, BWTF-tested by Surfrider Oʻahu
Kaiaka Bay is the smaller, quieter bay just west of Haleʻiwa Beach Park, with a state recreation area and reef-protected lagoon — and a BWTF sample point. The latest Surfrider BWTF sample (2026-04-19) measured 20 MPN/100mL — within the 130 BAV threshold. The Hawaii DOH does not routinely test this beach.
Kaiaka Bay is a small protected bay west of Haleʻiwa, partially sheltered by a reef and stretching inland to the Anahulu Stream mouth at the south end. The bay's geometry and the nearby Paukauila and Anahulu streams mean stream input is part of the picture.
Surfrider's BWTF reading at Kaiaka Bay was 20 MPN/100mL — well within the 130 BAV threshold. The small reef-protected lagoon flushes adequately during most conditions.
After heavy rain, the streams to the south can pump bacteria into the bay. The 72-hour rule applies, with extra caution for the southern end near the stream mouths. Better swimming options on the same coast: Haleʻiwa Beach Park (lifeguarded, BWTF-tested) and Waimea Bay further east.
The Hawaii Department of Health does NOT routinely test Kaiaka Bay. The community-tested readings on this page come from the Surfrider Foundation Blue Water Task Force, a volunteer-led monitoring program run by the Surfrider Oʻahu chapter.
BWTF samples Kaiaka Bay biweekly using the IDEXX Enterolert method (MPN/100mL), and compares results against the same 130 Beach Action Value DOH uses statewide. See our overview of citizen water-quality testing in Hawaiʻi for the methodology and how BWTF data fits with DOH coverage.
Sandy entry from the Kaiaka Bay State Recreation Area. The northern end (away from the stream mouths) is the cleanest. Watch for currents around the bay's narrow opening.
Summer mornings before north-shore traffic builds. The bay is quieter and less crowded than Haleʻiwa Beach Park to the east. Family-friendly in summer; winter brings powerful surf to the open coast nearby (Kaiaka itself stays calmer than the open beaches).
Off Haleʻiwa Road just west of Haleʻiwa town. Kaiaka Bay State Recreation Area has parking, restrooms, picnic tables, and camping. About 5 minutes from Haleʻiwa town center.
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⚠️ Important Disclaimer
Safe to Swim Hawaii is an independent passion project — not affiliated with the Hawaii Department of Health, the Surfrider Foundation, or any government agency. Bacteria readings on this page come from the Surfrider Blue Water Task Force, a volunteer-led monitoring program. Readings are point-in-time samples; conditions change with weather, runoff, and wave patterns. They are not real-time measurements and may not reflect current conditions.
Always verify current water quality conditions with the Hawaii DOH Clean Water Branch and BWTF directly before entering the water.
This site does not recommend or advise anyone to swim at any beach. We share publicly available data and geographic analysis so you can make your own informed decisions. By using this site you accept full responsibility for your own safety. See our Terms of Use for full details.
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