Best dive sites, water quality, and safety across all Hawaiian islands
Hawaii sits in the middle of the Pacific with some of the world's clearest and most biodiverse waters. With over 680 endemic marine species found nowhere else on Earth, 100+ foot visibility on good days, manta ray night dives, and ancient lava formations, Hawaii ranks among the top scuba destinations globally. Each island offers a distinctly different diving experience.
Hawaii's most famous dive. Giant Pacific manta rays (up to 16-foot wingspan) feed on plankton attracted by dive lights. One of the top 10 dives in the world. Kneeling on the sandy bottom at 30-40 feet watching mantas overhead is unforgettable.
Marine Life Conservation District with extraordinary visibility and coral. Spinner dolphins resident in the bay. Best reached by boat or kayak. Shallow enough for snorkel or OW scuba, with deeper areas for advanced divers.
Multiple green sea turtle cleaning stations where turtles hover motionlessly while reef fish clean parasites from their shells. Consistent and magical encounters.
The inside of Molokini is great for snorkel, but the back wall drops 300+ feet in crystal clear water teeming with pelagics. Advanced dive. Hammerhead sharks, white-tip reef sharks, and wahoo cruise the wall. Boat only.
Massive lava caverns where sunlight filters through cracks, creating a cathedral-like atmosphere. Spinner dolphins frequently rest nearby. Considered one of the top dive sites in the Pacific. Dive operators run trips from Maui.
Multiple green turtle cleaning stations and abundant reef fish. Shallow and great for beginners. Located near Big Beach on Maui's south shore.
Two intentionally sunk wrecks off Oʻahu's west coast. The Mahi (a former minesweeper) sits at 60-90 feet and is covered with hard and soft corals, resident sea turtles, and enormous schools of fish. One of Hawaii's best wreck dives.
Just 2 miles offshore from Waikiki Beach, this reef dive offers reliable green sea turtle encounters at 30-50 feet. Great for beginners. Numerous Waikiki dive operators offer morning and afternoon boat trips.
One of Kauaʻi's best shore dives in the Poʻipū area. Easy entry, 20-60 foot depths, resident sea turtles, and diverse reef fish. Great for all levels. Calm water most of the year.
Summer-only boat dives along the Nā Pali cliffs offer dramatic lava arches, sea caves, and abundant marine life. Advanced conditions with currents and surge. Some of the most dramatic underwater scenery in Hawaii.
Scuba divers are submerged in ocean water for extended periods. After heavy rain, shallow reef dives near shore can have elevated bacteria levels and significantly reduced visibility. Wait 48–72 hours after heavy rain for conditions to improve. Open-ocean and leeward dive sites are much less affected. Always check local conditions with your dive operator before booking.
Top-rated experiences near this beach. Check water quality above, then plan your trip.
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Free water quality alerts before your dives.
Hawaii’s Department of Health monitors approximately 57 beaches statewide through regular bacteria testing. However, with over 300 swimmable beaches across the islands, many popular spots have no regular testing program. Water quality varies significantly based on rainfall, stream proximity, coastal development, and ocean circulation patterns.
After heavy rain, streams and storm drains carry bacteria, sewage, pesticides, and sediment into coastal waters. The DOH recommends staying out of the ocean for at least 48 to 72 hours after heavy rain, even if the water appears clear. Brown or murky water is a visible sign of contamination, but bacteria can be present in clear water near stream mouths.
This site aggregates data from six sources — DOH advisories, USGS stream monitoring (25 stations), NOAA tide and temperature data, NDBC wave buoys, NWS weather alerts, and City & County of Honolulu water testing — to provide a more complete picture than any single source.
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.
⚠️ Important Disclaimer
Safe to Swim Hawaii is independent, not affiliated with the Hawaii DOH. Always dive with a certified operator and check current conditions. Water quality ratings are not real-time measurements.
Verify water quality with the Hawaii DOH Clean Water Branch.
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. 🤙