The southern flank of Kaneohe Bay — Heʻeia State Park area, BWTF-tested
South Kaneohe Bay is the southern flank of the larger Kaneohe Bay system on windward Oʻahu, around the Heʻeia State Park area — a Surfrider BWTF sample point. The latest Surfrider BWTF sample (2026-04-19) measured 145 MPN/100mL — exceeding the 130 BAV threshold. The Hawaii DOH does not routinely test this beach.
Kaneohe Bay receives multiple stream inputs: Heʻeia, Kaʻalaea, Waikalua, and others all drain into the bay's south end. Combined with the bay's protected geometry behind the barrier reef, the area has a structurally higher baseline bacteria reading than open-coast Oʻahu beaches.
The latest BWTF reading measured 145 MPN/100mL — modestly exceeding the 130 BAV threshold. Readings here can swing significantly with rainfall: a few days after heavy rain the streams pump bacteria; in a long dry window the bay clears.
Ancient Hawaiians used Kaneohe Bay's sheltered geometry for fishponds and aquaculture; the same protection makes it sensitive to stream-borne contaminants today. Always check recent rainfall before swimming, and avoid the immediate stream-mouth areas.
The Hawaii Department of Health does NOT routinely test South Kaneohe 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 South Kaneohe 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.
Heʻeia State Park has the best protected access. Avoid the immediate stream-mouth zones (Heʻeia, Kaʻalaea). The reef-protected channels are calm but slow to flush — pick spots away from canals and harbors.
After at least 5–7 dry days. The windward side gets more rain than leeward Oʻahu, so dry windows are rarer. Summer trade-wind days are often clearer. Avoid the bay for 4–7 days after a major storm.
Heʻeia State Park is off Kamehameha Highway in Kaneohe. Several public access points along the bay's south flank. Boat launches at Heʻeia Pier and Heʻeia Kea Boat Harbor. Sandbar tours leave from the boat harbor on calm days.
Free alerts when water quality changes at your beach.
No spam. Just safety alerts for your trip.
⚠️ 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.
When in doubt, don't go out. 🤙