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OAHU · WEST SIDE

Ko Olina Lagoons

Water quality status and bacteria risk rating

Also known as: Disney Beach, Aulani Beach

📍 On Oʻahu's west coast, about 30 minutes from Waikiki, near Aulani Disney and the Four Seasons

Checking live advisories…
30-Day Water Quality History
30/30 days advisory-free · no DOH advisories posted in the past 30 days
Sep 25 · No active advisorySep 26 · No active advisorySep 27 · No active advisorySep 28 · No active advisorySep 29 · No active advisorySep 30 · No active advisoryOct 1 · No active advisoryOct 2 · No active advisoryOct 3 · No active advisoryOct 4 · No active advisoryOct 5 · No active advisoryOct 6 · No active advisoryOct 7 · No active advisoryOct 8 · No active advisoryOct 9 · No active advisoryOct 10 · No active advisoryOct 11 · No active advisoryOct 12 · No active advisoryOct 13 · No active advisoryOct 14 · No active advisoryOct 15 · No active advisoryOct 16 · No active advisoryOct 17 · No active advisoryOct 18 · No active advisoryOct 19 · No active advisoryOct 20 · No active advisoryOct 21 · No active advisoryOct 22 · No active advisoryOct 23 · No active advisoryOct 24 · No active advisory
Sep 25 through Oct 24
EPA recreational threshold: 130 CFU/100mL enterococcus
Trend: — stable
advisory-free Brown Water Advisory Beach Advisory (bacteria)
Historical Pattern · 3-year monthly
January — 86% advisory-free historicallyFebruary — 85% advisory-free historicallyMarch — 87% advisory-free historicallyApril — 82% advisory-free historicallyMay — 92% advisory-free historicallyJune — 100% advisory-free historicallyJuly — 100% advisory-free historicallyAugust — 88% advisory-free historicallySeptember — 89% advisory-free historicallyOctober — 100% advisory-free historicallyNovember — 97% advisory-free historicallyDecember — 84% advisory-free historically JFMAMJJASOND
Historically most advisory-free in June (100% advisory-free) and most advisoried in April (82% advisory-free). Current 30-day window is tracking about average for October.
Source: Hawaii DOH Clean Water Branch · Updated 2026-10-25
Ko Olina Water-Quality Decision

Fast Ko Olina check: start with the current DOH status and dated 30-day advisory history above. That history counts days with posted notices; it is not a current water test. The lagoons circulate more slowly than open-ocean beaches. Follow any active DOH notice until it is lifted, and stay out of brown or murky water.

Compare hotel beach water quality→ See the Oʻahu 14-day trend→ Check current advisories and closures→
⚠
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. Avoid swimming during or immediately after heavy rain and stay out of brown or murky water. Elapsed time and clear-looking water do not establish water quality. Follow any DOH advisory affecting this beach until DOH lifts it.
Learn more about brown water advisories →
Book Tours & Activities at Ko Olina

Ko Olina is a great base for West Oʻahu adventures. When lagoon conditions are clear, these tours make the most of your time.

⛵ Ko Olina Catamaran Sail & Snorkel
3-hour catamaran snorkel with lunch, departing from Ko Olina. 4.8★ (640 reviews).
Viator
Waikīkī Snorkeling Cruise
Individual snorkeling cruise departing Honolulu. Review this trip’s itinerary, requirements, and availability.
GetYourGuide
🌿 North Shore Tour from Ko Olina
Full-day North Shore adventure with Waimea Valley waterfall. Departs from Ko Olina. 4.9★ (37 reviews).
Viator
Waikīkī Snorkeling Cruise
Individual snorkeling cruise departing Honolulu. Review this trip’s itinerary, requirements, and availability.
GetYourGuide

Tours listed via Viator and GetYourGuide. Safe to Swim Hawaii may earn a commission if you book, at no extra cost to you.

Historical Bacteria Risk
⚠ Historical rating — this is based on long-term testing data, not current conditions. The state of Hawaii is often slow to test beaches and update advisories. Always check the water yourself and avoid brown or murky water.
Moderate Risk 2 / 5

Ko Olina's four man-made lagoons have generally acceptable water quality under normal conditions. The lagoons self-clean via ocean currents through breakwater openings, but their enclosed shape means water turns over more slowly than at open beaches.

Landfill proximity: The Waimanalo Gulch Landfill (Oahu's only municipal landfill) sits directly behind Ko Olina. In 2010–2011, heavy storms caused contaminated stormwater and medical waste to reach the ocean, closing the lagoons. An EPA consent decree was completed in 2023 with infrastructure upgrades. No major stream runoff feeds into the lagoons under normal conditions.

Based on: DOH Tier 1 monitoring, EPA consent decree history, man-made lagoon circulation assessment

⚠️ After-Rain Precautions

The 72-hour rule applies to Ko Olina's lagoons. Because the lagoons are enclosed with limited water exchange, bacteria and pollutants from storm runoff can take longer to flush out than at open beaches. Be especially cautious after heavy rainfall. The proximity of the Waimanalo Gulch Landfill means severe storms could potentially carry additional contaminants.

Ko Olina Lagoons Area Hotels — Historical Beach Water Quality
🏨 Aulani Disney Resort
Lagoon 2, directly on the water
Moderate
🏨 Four Seasons Ko Olina
Lagoon 1, west end of resort
Moderate
Explore More Oʻahu Beaches
Waikiki Beach — Water Quality Today→ Hanauma Bay — Snorkeling Water Quality→ Kailua Beach — Windward Oʻahu→ Is It Safe to Swim After Rain?→ Electric Beach (Kahe Point) — Nearby Snorkeling→ Ala Moana Beach — Honolulu→ Sunset Beach — North Shore→ Best Sunset Beaches in Hawaii→
Related Guides
Ko Olina vs Waikiki — Which Is Better?→ Ko Olina Complete Beach Guide→ Best Oʻahu Beaches for Families→ All Oʻahu Beaches→ Worst Beaches for Bacteria→ Which Beach Is My Hotel On?→ Swimming After Rain in Hawaii→ Hawaii Brown Water Advisory — Live Status→
Beaches Near Kapolei
Explore → JW Marriott Ihilani Ko Olina — Beach & Water Quality Guide→ Hawaii Water Quality Today — All Islands→ Waikiki vs Ko Olina — Full Comparison→ Best Family Beaches in Hawaii→ Hawaii Beach Accessibility Guide→ Hawaii Beach Crowds — When to Go→ Beaches Near Aulani Resort — Water Quality Guide→ Hazards at Ko Olina Lagoons — What to Know→ Ko Olina Area Guide — Beaches, Water Quality & Tips→ Ala Moana Vs Ko Olina — Water Quality Compared→ Electric Beach Vs Ko Olina — Water Quality Compared→ Hanauma Bay Vs Ko Olina — Water Quality Compared→ Ko Olina Vs Ewa Beach — Water Quality Compared→ Ko Olina Vs Hapuna — Water Quality Compared→ Ko Olina Vs Kaanapali — Water Quality Compared→ Ko Olina Vs Makaha — Water Quality Compared→ Ko Olina Vs Poipu — Water Quality Compared→ Ko Olina Vs Poipu Families — Water Quality Compared→ Ko Olina vs Wailea — Water Quality Compared→ Ko Olina Hotels vs Waikiki Hotels — Compared→ Ko Olina Lagoon 1 vs Lagoon 4 — Water Quality→
Ko Olina Lagoons Water Quality by Month
January February March April May June July August September October November December
Activities at Ko Olina Lagoons
🤿 Snorkeling at Ko Olina Lagoons→ 🏄 Surfing at Ko Olina Lagoons→ 👶 Swimming with Kids at Ko Olina Lagoons→ 🛶 Kayaking at Ko Olina Lagoons→
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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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