Mosquitoes -- These pesky insects are not native to Hawaii but arrived as larvae stowed away in water barrels on the ship Wellington in 1826, when it anchored in Lahaina. There's not a whole lot you can do about them, except to apply commercial repellent, which you can pick up at any drugstore.

Centipedes -- These segmented bugs with a jillion legs come in two varieties: 6- to 8-inch-long brown ones and 2- to 3-inch-long blue guys. Both can really pack a wallop with their sting. Centipedes are generally found in damp, wet places, such as under woodpiles or compost heaps; wearing closed-toe shoes can help prevent stings. If you're stung, apply ice at once to prevent swelling. See a doctor if you experience extreme pain, swelling, nausea, or any other severe reaction.

Scorpions -- Rarely seen, scorpions are found in arid, warm regions; their stings can be serious. Campers in dry areas should always check their boots before putting them on and shake out sleeping bags and bed rolls. Symptoms of a scorpion sting include shortness of breath, hives, swelling, and nausea. In the unlikely event that you're stung, apply diluted household ammonia and cold compresses to the area of the sting and seek medical help immediately.

Hiking Safety 

In addition to taking the appropriate precautions regarding Hawaii's bug population, hikers should always let someone know where they're heading, when they're going, and when they plan to return; too many hikers get lost in Hawaii because they don't let others know their basic plans. And make sure you know how strenuous the route and trail you will follow are -- don't overestimate your ability.

Before you head out, always check weather conditions with the National Weather Service (; tel. 808/973-5286 on Oahu). Do not hike if rain or a storm is predicted; flash floods are common in Hawaii. Hike with a pal, never alone. Plan to finish your hike at least an hour before sunset; because Hawaii is so close to the equator, it does not have a twilight period, and thus it gets dark quickly after the sun sets. Wear hiking boots, a sun hat, clothes to protect you from the sun and from getting scratches, and high-SPF sunscreen on all exposed areas of skin. Take plenty of water, basic first aid, a snack, and a bag to pack out what you pack in. Stay on the trail. Watch your step. It's easy to slip off precipitous trails and into steep canyons. Many experienced hikers and boaters today pack a cellphone in case of emergency; just dial tel. 911.

Vog -- The volcanic haze dubbed "vog" is caused by gases released when molten lava -- from the continuous eruption of Kilauea volcano on the Big Island -- pours into the ocean. Some people claim that long-term exposure to the hazy, smoglike air has caused bronchial ailments, but it's highly unlikely to cause you any harm in the course of your visit.

There actually is a vog season in Hawaii: the fall and winter months, when the trade winds that blow the fumes out to sea die down. Then vog is felt not only on the Big Island, but also as far away as Maui and Oahu.

One more word of caution: If you're pregnant or have heart or breathing problems, you should avoid exposure to the sulfuric fumes that are ever present in and around the Big Island's Hawaii Volcanoes National Park.

Ocean Safety 

Because most people coming to Hawaii are unfamiliar with the ocean environment, they're often unaware of the natural hazards it holds. With just a few precautions, your ocean experience can be a safe and happy one. An excellent book is All Stings Considered: First Aid and Medical Treatment of Hawaii's Marine Injuries, by Craig Thomas and Susan Scott (University of Hawaii Press, 1997).

Note that sharks are not a big problem in Hawaii; in fact, they appear so infrequently that locals look forward to seeing them. Since records have been kept, starting in 1779, there have been only about 100 shark attacks in Hawaii, of which 40% have been fatal. Most attacks occurred after someone fell into the ocean from the shore or from a boat; in these cases, the sharks probably attacked after the person was dead. But here are the general rules for avoiding sharks: Don't swim at sunrise, at sunset, or where the water is murky due to stream runoff -- sharks may mistake you for one of their usual meals. And don't swim where there are bloody fish in the water, as sharks become aggressive around blood.

Enjoying the Ocean & Avoiding Mishaps -- The Pacific Whale Foundation has a free brochure called Maui Adventure Guide that introduces visitors to Hawaii's ocean, beaches, tide pools, and reefs. Although written for Maui (with maps showing Maui's beaches), it's a great general resource on how to stay safe around the ocean, with hints on how to assess weather before you jump into the water and the best ways to view marine wildlife. To get the brochure, call tel. 808/249-8811, ext. 1, or visit

Seasickness -- The waters in Hawaii can range from as calm as glass (off the Kona Coast on the Big Island) to downright frightening (in storm conditions); they usually fall somewhere in between. In general, expect rougher conditions in winter than in summer. Some 90% of the population tends toward seasickness. If you've never been out on a boat, or if you've been seasick in the past, you might want to heed the following suggestions:

  • The day before you go out on the boat, avoid alcohol, caffeine, citrus and other acidic juices, and greasy, spicy, or hard-to-digest foods.
  • Get a good night's sleep the night before.
  • Take or use whatever seasickness prevention works best for you -- medication, an acupressure wristband, gingerroot tea or capsules, or any combination. But do it before you board; once you set sail, it's generally too late.
  • While you're on the boat, stay as low and as near the center of the boat as possible. Avoid the fumes (especially if it's a diesel boat); stay out in the fresh air and watch the horizon. Do not read.
  • If you start to feel queasy, drink clear fluids like water, and eat something bland, such as a soda cracker.

Stings -- The most common stings in Hawaii come from jellyfish, particularly Portuguese man-of-war and box jellyfish. Since the poisons they inject are very different, you need to treat each type of sting differently.

A bluish-purple floating bubble with a long tail, the Portuguese man-of-war is responsible for some 6,500 stings a year on Oahu alone. These stings, although painful and a nuisance, are rarely harmful; fewer than 1 in 1,000 requires medical treatment. The best prevention is to watch for these floating bubbles as you snorkel (look for the hanging tentacles below the surface). Get out of the water if anyone near you spots these jellyfish.

Reactions to stings range from mild burning and reddening to severe welts and blisters. All Stings Considered recommends the following treatment: First, pick off any visible tentacles with a gloved hand, a stick, or anything handy; then rinse the sting with salt- or fresh water, and apply ice to prevent swelling and to help control pain. Avoid folk remedies like vinegar, baking soda, or urinating on the wound, which may actually cause further damage. Most Portuguese man-of-war stings will disappear by themselves within 15 to 20 minutes if you do nothing at all to treat them. Still, be sure to see a doctor if pain persists or a rash or other symptoms develop.

Transparent, square-shaped box jellyfish are nearly impossible to see in the water. Fortunately, they seem to follow a monthly cycle: 8 to 10 days after the full moon, they appear in the waters on the leeward side of each island and hang around for about 3 days. Also, they seem to sting more in the morning hours, when they're on or near the surface.

The stings can cause anything from no visible marks to hivelike welts, blisters, and pain lasting from 10 minutes to 8 hours. All Stings Considered recommends the following treatment: First, pour regular household vinegar on the sting; this will stop additional burning. Do not rub the area. Pick off any vinegar-soaked tentacles with a stick. For pain, apply an ice pack. Seek additional medical treatment if you experience shortness of breath, weakness, palpitations, muscle cramps, or any other severe symptoms. Most box-jellyfish stings disappear by themselves without any treatment.

A new product, just on the market, is Jellyfish Squish, made by Coastal Solutions (; tel. 912/353-3368). It has been getting rave reviews from ocean enthusiasts; it takes away the sting quickly. It's best to order some online before you get to Hawaii.

Punctures -- Most sea-related punctures come from stepping on or brushing against the needlelike spines of sea urchins (known locally as wana). Be careful when you're in the water; don't put your foot down (even if you have booties or fins on) if you can't clearly see the bottom. Waves can push you into wana in a surge zone in shallow water. The spines can even puncture a wet suit.

A sea urchin puncture can result in burning, aching, swelling, and discoloration (black or purple) around the area where the spines entered your skin. The best thing to do is to pull out any protruding spines. The body will absorb the spines within 24 hours to 3 weeks, or the remainder of the spines will work themselves out. Again, contrary to popular thought, do not urinate or pour vinegar on the embedded spines -- this will not help.

Cuts -- All cuts obtained in the marine environment must be taken seriously because the high level of bacteria present in the water can quickly cause the cut to become infected. The best way to prevent cuts is to wear a wet suit, gloves, and reef shoes. Never touch coral; not only can you get cut, but you also can damage a living organism that took decades to grow. The symptoms of a coral cut can range from a slight scratch to severe welts and blisters. All Stings Considered recommends gently pulling the edges of the skin open and removing any embedded coral or grains of sand with tweezers. Next, scrub the cut well with fresh water. If pressing a clean cloth against the wound doesn't stop the bleeding, or the edges of the injury are jagged or gaping, seek medical treatment.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.