Are there mosquitoes in Hawaii? Yes, including the ones that spread dengue.

Yes. The Asian tiger mosquito lives on all the main islands and Aedes aegypti on Hawaii Island, both day-biting species that spread dengue, though there has been no local dengue spread since a 2015–16 outbreak on Hawaii Island (the Big Island). Resorts on the dry leeward coasts tend to see few bites, and the wet windward rainforest sees the most. For a trip from the mainland, no travel clinic, vaccine or medicine is needed.

Dengue arrives with travelers

Dengue isn't endemic in Hawaii. The state Department of Health says it currently sees cases only in travelers, and recent years have brought around a dozen travel-related cases a year, all caught elsewhere and mostly in people returning from Pacific islands. That is well above the handful a year Hawaii used to see, and in April 2025 the department warned that more imported cases raise the risk of local spread.

The risk comes from the mosquitoes already here. A traveler who arrives with dengue and gets bitten can pass the virus to local mosquitoes, and that has happened before. In the 2015–16 Hawaii Island outbreak, 264 people were confirmed ill between September 2015 and March 2016, a 2020 study in Public Health Reports found. About 26 were visitors, 37 were hospitalized, and none developed severe dengue or died. Entomologists found the virus only in tiger mosquitoes. An earlier outbreak, in 2001–02, was linked to travel from French Polynesia.

For a visitor, that adds up to two habits. Both dengue mosquitoes bite in daylight, with peaks in the morning and late afternoon, so repellent goes on before trails and garden walks as well as at dusk. And if you arrive from a Pacific island with dengue, or a fever starts during your stay, see a doctor and say where you've been. Keeping bites down also keeps local mosquitoes from picking up the virus, which is the health department's main concern. Our dengue routine has the daily schedule, and our guide to bites in a dengue zone lists the symptoms to watch for.

Hawaii has no malaria, no documented local West Nile and no Lyme disease ticks, and no local chikungunya or Zika has been reported. Hikers have one non-insect item to know about, leptospirosis from fresh water, and state health advice, as reported in local media, is to avoid wading or swimming in streams and waterfall pools with cuts or scrapes and to boil or treat stream water before drinking.

Where the bites are

The Asian tiger mosquito, the most common species caught at the 2015–16 outbreak sites, bites by day, mostly in shade and after rain. The southern house mosquito, a Culex, takes over at dusk and at night. The dry leeward coasts tend to be light, including Waikiki, West Maui and Wailea, the Kona-Kohala coast and Poipu on Kauai. Hana and the waterfall stops on the Road to Hana have a reputation as the worst place for mosquitoes on Maui, and the rainforest around Hilo and Hawaii Volcanoes National Park, Kauai's wetter north shore and Oahu's windward valleys tend to be buggy too.

Timing by season

Any month works for a resort stay on the leeward coasts. The wetter months, roughly November to March, tend to bring more rain and more mosquitoes to the windward sides, so a winter drive to Hana or a hike near Hilo calls for repellent before you leave the car. Winter is no safer for dengue, since travel-related cases turn up all year and the 2015–16 outbreak ran from September through March.

Where you're going

How the main stops compare, in any month.

Adding Tahiti or Guam to the trip? Our Tahiti and Guam briefings cover the dengue picture there.

What travelers report

Paraphrased from TripAdvisor threads and linked so you can read them in full. Neither is dated, and rain, shade and which side of the island you're on change the picture from one day to the next.

• Hana, Maui

  In a thread asking about 'ravenous' Hana mosquitoes, posters called Hana the buggiest part of Maui and advised bringing repellent, especially for hikes. TripAdvisor ↗

• Kauai

  A visitor asked what was biting them. Replies blamed tiny biters they could not see; some posters suspected sand flies, and others disputed that. TripAdvisor ↗

One rule outlasts the trip. Any fever during or after your trip means a doctor visit, and you tell them you were in Hawaii, and anywhere else you went.

Traveler questions