Like any tropical climate, Hawaii is home to lots of bugs. Most of them won't harm you. However, watch out for mosquitoes, centipedes, and scorpions, which do sting and may cause anything from mild annoyance to severe swelling and pain.

Mosquitoes 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, those 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 wood piles 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.

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.

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.

Before you head out, always check weather conditions with the National Weather Service (tel. 808/973-4380 on Oahu; Hike with a pal, never alone. 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 water. 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.

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. The vog is felt not only on the Big Island, but also as far away as Oahu.

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 (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 general rules for avoiding sharks are: 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.

The waters in Hawaii can range from as calm as glass 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 had seasickness 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 such clear fluids as water, and eat something bland, such as a soda cracker.

The most common stings in Hawaii come from jellyfish, particularly Portuguese man-of-war and box jellyfish. Because 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, such as 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.

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 any protruding spines out. 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 wisdom, do not urinate or pour vinegar on the embedded spines -- this will not help.

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 can also 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.

Enjoying the Ocean & Avoiding Mishaps

The Pacific Whale Foundation has a free brochure called Enjoying Maui's Unique Ocean Environment 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. 808/856-8316 or visit

Everything You've Always Wanted to Know About Sharks -- The Hawaii State Department of Land and Natural Resources has launched a website,, that covers the biology, history, and culture of these carnivores. It also provides safety information and data on shark bites in Hawaii.

Don't Get Burned: Smart Tanning Tips

Hawaii's Caucasian population has the highest incidence of malignant melanoma (deadly skin cancer) in the world. And nobody is completely safe from the sun's harmful rays: All skin types and races can burn. To ensure that your vacation won't be ruined by a painful sunburn, be sure to wear a strong sunscreen that protects against both UVA and UVB rays at all times (look for zinc oxide, benzophenone, oxybenzone, sulisobenzone, titanium dioxide, or avobenzone in the list of ingredients). Wear a wide-brimmed hat and sunglasses. Keep infants under 6 months out of the sun completely, and slather older babies and children with strong sunscreen frequently.

If you do get a burn, aloe vera, cool compresses, cold baths, and benzocaine can help with the pain. Stay out of the sun until the burn is completely gone.

General Safety

Although tourist areas are generally safe, visitors should always stay alert, even in laid-back Hawaii (and especially in Waikiki). It's wise to ask the island tourist office if you're in doubt about which neighborhoods are safe. Avoid deserted areas, especially at night. Don't go into any city park at night unless there's an event that attracts crowds -- for example, the Waikiki Shell concerts in Kapiolani Park. Generally speaking, you can feel safe in areas where there are many people and open establishments.

Avoid carrying valuables with you on the street, and don't display expensive cameras or electronic equipment. Hold on to your pocketbook, and place your billfold in an inside pocket. In theaters, restaurants, and other public places, keep your possessions in sight.

Oahu has seen a series of purse-snatching incidents, in which thieves in slow-moving cars or on foot have snatched handbags from female pedestrians. The Honolulu police department advises women to carry purses on the shoulder away from the street or, better yet, to wear the strap across the chest instead of on one shoulder. Women with clutch bags should hold them close to their chest. Muggings have also been recently reported at bus stops on the North Shore, so you may want to rent a car rather than take the bus if visiting that area.

Remember also that hotels are open to the public and that in a large property, security may not be able to screen everyone entering. Always lock your room door -- don't assume that once inside your hotel, you're automatically safe.

Burglaries of tourists' rental cars in hotel parking structures and at beach parking lots have become more common. Park in well-lighted and well-traveled areas, if possible. Never leave any packages or valuables visible in the car. If someone attempts to rob you or steal your car, do not try to resist the thief or carjacker -- report the incident to the police department immediately. Ask your rental agency about personal safety, and get written directions or a map with the route to your destination clearly marked.

Generally, Hawaii has the same laws as the mainland United States. Nudity is illegal in Hawaii. There are no legal nude beaches (despite what you may have read). If you are nude on a beach (or anywhere) in Hawaii, you can be arrested.

Smoking marijuana also is illegal. Yes, there are lots of "stories" claiming that marijuana is grown in Hawaii, but the drug is illegal; if you attempt to buy it or light up, you can be arrested.

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.