← All beaches & hotels
BIG ISLAND · KOHALA COAST

Anaehoomalu Bay

Also known as A-Bay — Waikoloa Resort Beach

Water quality status and bacteria risk rating

📍 Waikoloa, Big Island — Sheltered bay, beginner-friendly

Checking live advisories…
30-Day Water Quality History
30/30 days advisory-free · no DOH advisories posted in the past 30 days
Aug 28 · No active advisoryAug 29 · No active advisoryAug 30 · No active advisoryAug 31 · No active advisorySep 1 · No active advisorySep 2 · No active advisorySep 3 · No active advisorySep 4 · No active advisorySep 5 · No active advisorySep 6 · No active advisorySep 7 · No active advisorySep 8 · No active advisorySep 9 · No active advisorySep 10 · No active advisorySep 11 · No active advisorySep 12 · No active advisorySep 13 · No active advisorySep 14 · No active advisorySep 15 · No active advisorySep 16 · No active advisorySep 17 · No active advisorySep 18 · No active advisorySep 19 · No active advisorySep 20 · No active advisorySep 21 · No active advisorySep 22 · No active advisorySep 23 · No active advisorySep 24 · No active advisorySep 25 · No active advisorySep 26 · No active advisory
Aug 28 through Sep 26
EPA recreational threshold: 130 CFU/100mL enterococcus
Trend: — stable
advisory-free Brown Water Advisory Beach Advisory (bacteria)
Historical Pattern · 3-year monthly
January — 99% advisory-free historicallyFebruary — 79% advisory-free historicallyMarch — 100% advisory-free historicallyApril — 100% advisory-free historicallyMay — 100% advisory-free historicallyJune — 100% advisory-free historicallyJuly — 100% advisory-free historicallyAugust — 88% advisory-free historicallySeptember — 100% advisory-free historicallyOctober — 100% advisory-free historicallyNovember — 100% advisory-free historicallyDecember — 100% advisory-free historically JFMAMJJASOND
Historically most advisory-free in March (100% advisory-free) and most advisoried in February (79% advisory-free). Current 30-day window is tracking about average for September.
Source: Hawaii DOH Clean Water Branch · Updated 2026-09-27
⚠
If It Looks Brown, Don't Swim
Never enter the ocean when the water appears brown or murky, even if no advisory is posted. Hawaii is often slow to test beaches and update advisories — not every beach is monitored. After heavy rain, wait at least 72 hours and until the water clears before swimming.
Learn more about brown water advisories →
Historical Bacteria Risk
⚠ Historical rating — this is based on long-term testing data, not current conditions. Always check the water yourself and avoid brown or murky water.
Low Risk 1 / 5

Anaehoomalu Bay — universally called A-Bay — is one of the cleanest and calmest beaches on the Big Island. Located on the dry Kohala Coast near Waikoloa, the beach benefits from minimal rainfall and almost no agricultural or urban runoff. The natural reef that partially encloses the bay protects swimmers from open-ocean swells while allowing good water circulation.

The surrounding landscape is ancient lava field — there are no streams, no farmland, and no significant runoff sources that typically cause bacteria spikes at other Hawaiian beaches. DOH monitoring data shows that A-Bay consistently maintains excellent water quality, with bacteria violations being extremely rare.

Two ancient Hawaiian fishponds (Kuʻualiʻi and Kahapapa) sit just inland from the beach. These historic features are protected and add to the cultural significance of A-Bay. Green sea turtles frequently rest on the beach, and the bay offers excellent snorkeling along its rocky edges.

Based on: Dry lava coast with no stream runoff, natural reef protection, DOH Kohala Coast monitoring data

⚠️ The 72-Hour Rain Rule

Even on the dry Kohala Coast, heavy rain can temporarily affect water quality. The DOH recommends staying out of the ocean for at least 72 hours after heavy rain. A-Bay's excellent drainage and lack of runoff sources means it recovers quickly, but the rule still applies.

Anaehoomalu Bay Water Quality by Month
January February March April May June July August September October November December
Get Beach Safety Alerts

Free grouped email updates when Hawaii DOH issues or cancels advisories for your chosen island.

Island advisory changes only. Unsubscribe anytime.

Check all Hawaii beaches & hotels →

330+ beaches and hotels across all 6 islands

⚠️ 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.

Always verify current water quality conditions with the Hawaii Department of Health Clean Water Branch before entering the water.

This site does not recommend or advise anyone to swim at any beach. We share government 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. 🤙

© 2026 Safe to Swim Hawaii · safetoswimhawaii@gmail.com