Oaxaca city is quiet in winter. The coast asks a little more.

Are there mosquitoes in Oaxaca? Few in the city during the dry winter, and a few more on the coast at Puerto Escondido, Mazunte and Huatulco, where no-see-ums go for ankles in the evening. Dengue is endemic in the state, but 2026 has been a small year.

A small dengue year, with one coastal cluster

Mexico's health ministry counted 69 confirmed dengue cases and 2 deaths in Oaxaca state by October 19, 2026, against 202 cases and 3 deaths at the same point of 2025. That is 1.58 confirmed cases per 100,000 people, against 5.99 nationally. The largest 2026 cluster is on the coast. San Pedro Mixtepec, the municipality that holds Puerto Escondido, had 17 confirmed cases, and neighboring San Gabriel Mixtepec had 2. No other coastal municipality is named, so any cases around Huatulco, Zipolite and Mazunte are counted with the rest of the state.

The city isn't exempt. Oaxaca city sits at about 5,100 feet (1,550 m), which lowers the risk, but in the 2024 epidemic the capital had 1,244 confirmed cases, the most of any municipality in the state, and the suburb of Santa María Atzompa had 204. That sets it apart from Mexico City, where the CDC calls dengue risk minimal because of the altitude. In 2025 most of the state's cases were in the Papaloapan basin, far from the tourist routes, and 2026 has been quiet in the city.

Mexico's weekly bulletin reported no chikungunya, Zika or West Nile in Oaxaca in 2025 or 2026 through early October. The CDC lists malaria as "Rare in the states of Oaxaca, Sinaloa, Sonora, and Tabasco" and recommends bite precautions there, with no prevention medicine. If the trip continues into Chiapas, where the CDC does recommend malaria medicine, see a travel clinic 4–6 weeks before departure. The CDC doesn't recommend the yellow fever vaccine for Mexico.

Valley days and beach evenings

In the city and the Central Valleys, mosquitoes tend to be sparse in the dry season. The rainy season tends to bring more, mainly in neighborhoods with uncovered water storage, which is where the day-biting Aedes mosquito breeds. Carry repellent and use it in the daytime if mosquitoes are around. At Hierve el Agua, the mineral pools don't allow repellent or sunscreen, so swim first and apply it once you're dry.

On the coast, no-see-ums take over as the main complaint. These tiny biting midges go for ankles and lower legs at dusk, and a breeze grounds them, which is why Puerto Escondido's sea breeze has a reputation for helping. Spray feet, ankles and calves before dinner at a table on the sand. The lagoon at Manialtepec, west of Puerto Escondido, and the Ventanilla mangroves near Mazunte are likely spots for bites on a dusk boat tour. Our Barbados sand fly guide explains how the midges behave.

For dengue, put repellent on over sunscreen in the morning and again before sunset, and reapply after surfing or swimming. Choose a room with screens, a fan or air-conditioning, and use the bed net in open-air cabañas. An uncovered bucket or plant saucer at a rental can breed mosquitoes even in the dry season, so tip out standing water.

Where you're going

Scores are for a December–April trip.

Our Mexico briefing compares every region, including the malaria areas in Chiapas and Campeche, and the Cancún & Riviera Maya briefing covers the Caribbean coast.

What travelers report

Paraphrased from TripAdvisor forum threads and linked so you can read them in full. None is dated and most of the threads are older, so weather and where you stay can change the picture.

• Oaxaca city · February

  Asked about mosquitoes in February, posters said there are few in Oaxaca city in the dry season. TripAdvisor ↗

• Puerto Escondido · November to April

  A poster said mosquitoes are not a big problem in the November to April dry season and that the breeze helps compared with Huatulco. Posters said no-see-ums biting the ankles in the evening were the more common nuisance. TripAdvisor ↗

• Puerto Escondido (Zicatela)

  A reply said there are a few more mosquitoes around Zicatela than in other parts of town. TripAdvisor ↗

• Puerto Escondido · dry season

  A poster explained that mosquitoes breed in standing water and stay near where they hatch, so an uncovered bucket or flower pot at a rental can create a local problem even in the dry season. TripAdvisor ↗

One rule outlasts the trip. Any fever during the trip or within two weeks of returning means a doctor visit, and you tell the doctor you were in Oaxaca, including whether the coast or Chiapas was on the route.

Traveler questions