Beach water quality and lagoon safety guide
📍 Ko Olina, West Oʻahu — 92-1185 Aliʻinui Dr
Ko Olina's man-made lagoons, including the lagoon fronting Aulani Resort, have consistently excellent water quality. The engineered lagoons maintain ocean connection while protecting against swell and limiting stormwater intrusion. DOH monitoring data for Ko Olina lagoons historically shows very low bacteria counts.
The primary swimming areas at Aulani are the resort's own chlorinated pools — not the lagoon — so most guests are in water that is tested and treated daily. The lagoon beach is ideal for wading, boogie boarding, and calm ocean swimming.
Based on: Ko Olina lagoon DOH monitoring data, engineered lagoon design, limited development runoff
Even Ko Olina's lagoons can see elevated bacteria after heavy rain. Stormwater from West Oʻahu can reach the lagoons via runoff. The DOH recommends waiting at least 72 hours after heavy rain before swimming in ocean waters anywhere in Hawaiʻi.
Aulani fronts Ko Olina Lagoon 4, one of four crescent-shaped man-made lagoons at Ko Olina Resort. The lagoon offers calm, protected swimming in clear water typically 3–5 feet deep at the center. Sand bottom is soft and gently sloping — perfect for families with young children.
Beyond the lagoon, Aulani features the Waikolohe Valley pool complex with a lazy river, waterslides, a dedicated kiddie area, and a snorkeling pool stocked with tropical fish. All resort pool water is chlorinated and tested regularly.
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⚠️ Important Disclaimer
Safe to Swim Hawaii is an independent passion project — not affiliated with the Hawaii Department of Health or any government agency. Water quality ratings are estimates based on publicly available data and are not real-time measurements.
Always verify current conditions with the Hawaii Department of Health Clean Water Branch before swimming.
When in doubt, don't go out. 🤙