Which Oʻahu beach is right for your trip? Honest comparison.
Best for: swimming, kayaking, windsurfing, beach walks, locals' experience, no fees or reservations
Best for: snorkeling, marine sanctuary, seeing tropical fish, guided reef tours, bucket-list experience
These beaches serve different purposes. Go to Hanauma Bay for snorkeling. Go to Kailua for beach activities and a more local vibe. If possible, do both on different days.
Sandy beach, minimal reef. Not a snorkeling destination.
Marine sanctuary, coral reef, 400+ fish species. Hawaii's #1 snorkel spot.
2.5 miles of white sand, calm water, open ocean feel. Outstanding.
Good swimming in the bay, but rocky entry in some areas. Fine for most visitors.
Generally good, but more affected by rain runoff (Kawainui Canal).
Protected sanctuary, excellent quality, minimal runoff risk. Both good — tie.
Free, no reservations, open daily, easy parking. Take the bus or drive.
$25/person fee, advance reservations required, closed Tuesdays, limited parking.
Charming Kailua town, local coffee shops, kayak rentals, windward O'ahu feel.
Touristy but managed well. Educational marine center. Required briefing video.
Hanauma Bay reservations sell out weeks ahead. The bay is closed Tuesdays. Book at honolulu.gov before you arrive in Hawaii. Entry fee: $25/person (free for Hawaii residents and children under 13). Without a reservation, you cannot enter.
Top-rated experiences near this beach. Check water quality above, then plan your trip.
Tours listed via Viator and GetYourGuide. Safe to Swim Hawaii may earn a commission if you book, at no extra cost to you.
Free alerts when advisories change at your beach.
The 72-hour rule is the standard guideline from the Hawaii Department of Health: avoid swimming for at least 72 hours after heavy rain stops, especially near stream mouths, canal outlets, and areas with brown or discolored water. This applies to all beaches across all islands.
Bacteria from urban runoff, agricultural land, and aging cesspool systems enters the ocean through streams and storm drains. Hawaii has approximately 88,000 cesspools — more than any other state — many of which leak untreated sewage into groundwater that eventually reaches the coast. Beaches near known cesspool contamination areas carry higher risk, particularly after rainfall.
Independent passion project — not affiliated with Hawaii DOH. Ratings not real-time. Verify with Hawaii DOH.
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. 🤙
Safe to Swim Hawaii aggregates water quality data from six independent sources to provide broader coverage than any single agency. Our sources include the Hawaii Department of Health Clean Water Branch (beach advisories and bacteria testing), USGS National Water Information System (25 stream monitoring stations across all islands), NOAA CO-OPS (tide levels and water temperature), NDBC (wave buoys and ocean conditions), NWS Honolulu (weather and marine alerts), and City & County of Honolulu Environmental Services (Kailua Bay water testing and spill reports).
Historical bacteria risk ratings on this site are based on DOH testing data, Surfrider Foundation monitoring, geographic analysis (stream proximity, cesspool contamination areas, coastal development), and advisory frequency. These are historical assessments, not live measurements. Always check the live advisory status at the top of each page and verify conditions with the Hawaii DOH Clean Water Branch before entering the water.
⚠️ 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 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 DOH 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. 🤙