Hawaiʻi's beaches face the open Pacific. The water can look gentle and still knock an adult flat. Here is how the main hazards work, how to read the warning signs, and the habits that keep a beach day a good one.
Most of the islands drop quickly into deep water, so swell arrives with little to slow it. A wave that looks waist-high from the parking lot can land with enough force to throw a swimmer into the sand.
Health officials in Hawaiʻi track ocean injuries closely, and their figures are sobering: an analysis of Department of Health data covering 2007 to 2016 found visitors drowning at roughly nine times the rate of residents. Officials have also noted that many drownings happen far from a lifeguard tower. None of that should keep you off the sand. It is simply why local families plan beach days around the conditions, and why the habits below are worth adopting from the first morning of your trip.
The Hawaiʻi Tourism Authority sums up the core advice in a phrase you will see on signs and in hotel lobbies: if in doubt, don't go out.
Waves that break right on the sand or in knee-deep water. They are the leading cause of serious neck and spine injuries for bodyboarders and swimmers. A steep beach with a loud, thumping wave is the warning sign. Watch from dry sand, or swim only where waves break farther out.
Channels of water flowing back out to sea, often through gaps in the reef or beside rocks and piers. Look for darker, calmer-looking water, foam or debris moving seaward, and a gap in the line of breaking waves. They do not pull you under; they pull you away.
Seasonal swells can raise waves on one coast to many times their usual size within a day. When the National Weather Service issues a high surf advisory or warning, beaches on that shore are no place to swim, and even walking near the water can be dangerous.
Lava shelves, tide pools and blowholes look like safe vantage points. Occasional larger waves in a set can sweep across them without warning. Stay well back from wet rock, never turn your back to the ocean, and keep children close.
Coral and lava cut skin easily, and reef cuts get infected in warm water. Enter at a sandy channel, wear water shoes on rocky beaches, and never stand on coral; it is a living animal, and standing on it hurts you both.
The tropical sun is intense even on cloudy days. Dehydration and fatigue make people weaker swimmers. Bring water and shade, cover up with a rash guard, and get out before you are tired rather than after.
Snorkeling is one of the activities most often involved in visitor drownings in Hawaiʻi, and many incidents happen in water that looked calm. Practice with your mask and snorkel in shallow water before heading out, snorkel with a buddy, wear a flotation vest if you are not a strong swimmer, and lift your head and rest the moment you feel short of breath or uncomfortable. If you have a heart or lung condition, talk to your doctor before your trip.
Hawaiian monk seals often haul out to sleep on beaches, and green sea turtles rest on the sand too. Both are protected. NOAA recommends staying at least 50 feet from monk seals (150 feet from a mother and pup) and at least 10 feet from turtles. Give them room, keep dogs leashed and away, and let the animal leave on its own terms. Our beach rules and access guide has more on what the law requires.
After heavy rain, streams can flood quickly and carry runoff into the ocean. Do not cross a swollen stream to reach a beach, and stay out of brown, murky water near stream mouths and storm drains. The state Department of Health posts brown-water advisories when runoff affects coastal water. Our ocean conditions guide explains where to check.
For visitors, the biggest risks are powerful shorebreak, rip currents and large surf, especially at beaches without lifeguards. State Department of Health data show that visitors drown at a much higher rate than residents, and many incidents happen to people who were unfamiliar with Hawaii's ocean conditions.
It means waves are breaking with force directly onto the sand or in very shallow water. They can throw swimmers and bodyboarders into the bottom, causing serious neck and back injuries. Stay out of the water, or stay well back from where the waves are landing.
Stay calm and do not try to swim straight back to shore against the current. Float to conserve energy and raise an arm to signal for help. When the pull weakens, swim parallel to the beach and then angle back to shore. If you see someone else in trouble, alert a lifeguard or call 911 rather than going in after them.
Some are, on the right day. Choose a lifeguarded beach with a gentle sand entry, check the posted conditions, keep children within arm's reach in the water, and use a properly fitting life jacket for weak swimmers. Our family beaches guide lists good options on each island.
The Hawaii Beach Safety website shows lifeguard-reported hazards at guarded beaches statewide. The National Weather Service Honolulu office issues surf forecasts and high surf advisories. Ask the lifeguard when you arrive, because conditions can change within hours.