Mosquitoes in Puerto Viejo & Tortuguero: Malaria Advice, Sand Flies & Dengue (2026)

Puerto Viejo, Cahuita and Tortuguero sit in Limón, one of two provinces where the CDC lists malaria prevention medicine. Unlike Guanacaste and Arenal, Limón is outside the map for the CDC's chikungunya notice. The coast stays humid through the winter, and beach sand flies at dawn and dusk are the steady complaint.

Yes, and more than on the Pacific side in winter. Puerto Viejo, Cahuita and Tortuguero sit on a humid coast where beach sand flies bite at dawn and dusk and Tortuguero's canals can be heavy with mosquitoes. All three are in Limón province, one of two where the CDC lists malaria prevention medicine, and outside the map for its chikungunya notice.

Disease risk ElevatedLimón is one of two provinces where the CDC lists malaria prevention medicine, and dengue is present; the CDC's chikungunya notice map leaves the province unshaded.

Bite nuisance AnnoyingBeach sand flies at dawn and dusk in Puerto Viejo and Cahuita, and mosquitoes that can be heavy around Tortuguero's canals and lodges; the coast stays humid all winter.

CirculatingMalaria (Limón province, CDC)DengueSand flies on the beachOutside the CDC chikungunya mapNo yellow fever vaccine advised

CDC noticesLevel 2 · Chikungunya in northwest Costa Rica (the map leaves Limón out) · CDCLevel 1 · Global dengue (Costa Rica listed) · CDC

Travel clinicCDC lists malaria prevention medicine for Alajuela and Limón provinces, which covers Puerto Viejo, Cahuita and Tortuguero. Limón is outside its chikungunya notice map, while Guanacaste, Alajuela and Heredia are inside it, so bring the whole route to a travel clinic 4–6 weeks before departure.

Dec–Apr tripsThis coast has no reliable dry season and can be wet in December and January, so a winter trip finds it humid and biting while the Pacific side dries out. Check before you fly that the chikungunya map still leaves Limón out.

Data checkedOctober 2026 · sources

Malaria in Limón, and what the chikungunya map leaves out

The CDC's Costa Rica page describes malaria as "Present in the provinces of Alajuela and Limón." For "Alajuela and Limón Provinces" it lists atovaquone-proguanil, chloroquine, doxycycline, mefloquine and tafenoquine, and for all other areas it recommends bite precautions only.

What we suggest you do with this: book a travel-medicine appointment 4–6 weeks before departure. The CDC lists malaria prevention options for Alajuela and Limón provinces, which takes in the Caribbean coast and, if they're on your route, Arenal and La Fortuna. Bring the exact route and your nights in each place. Our malaria-zone checklist covers the rest.

The CDC's Level 2 notice, last reviewed July 30, 2026, describes "an outbreak of chikungunya in northwest Costa Rica," and its map shades Guanacaste, Alajuela, Heredia and parts of San José and Puntarenas. Limón is left unshaded, Tortuguero included, and by mid-September the Pan American Health Organization counted 2 of the country's 539 lab-confirmed 2026 cases there. The CDC recommends vaccination for travel to an outbreak area, so whether a Caribbean-only trip calls for it is a question for the clinic. If you're coming from Guanacaste or Arenal, you've been inside the map, so mention those stops.

Dengue is present too. In health ministry bulletins, Huetar Caribe, the ministry's region for Limón, had among the higher regional dengue rates in the first half of 2026. Its mosquito bites by day, so repellent goes on over sunscreen at breakfast. The CDC doesn't recommend yellow fever vaccine for Costa Rica, and Costa Rica's entry rule for arrivals from countries with yellow fever risk covers Colombia and Brazil but not Panama. A separate CDC Level 1 hepatitis A notice centers on San José province.

Beach sand flies and canal mosquitoes

On the beaches of Puerto Viejo, Playa Cocles and Cahuita, the bites come from what locals call sand flies, the tiny biting midges Americans know as no-see-ums. They go for feet, ankles and legs at dusk and in the early morning, and a breeze grounds them. Spray your lower legs before a late-afternoon beach session, shower afterward and wear light trousers for dinner. Mosquitoes tend to pick up after about 5 pm, and Cahuita National Park's shaded coastal trail is a likely spot for day-biters. Our Barbados sand fly guide explains how midges behave.

Tortuguero's canals, riverside lodges and trails have a reputation for heavy mosquitoes. Canal tours usually leave at dawn and in the late afternoon, and night walks and turtle tours put you out after dark, when malaria mosquitoes and phlebotomine sand flies bite. Those sand flies spread leishmaniasis, a skin infection, and the CDC Yellow Book names Costa Rica among its most common sources in travelers. They pass through ordinary nets. Wear permethrin-treated long sleeves, trousers and socks, sleep in a screened or air-conditioned room or under the lodge's net, and keep cuts clean and covered, as the CDC advises for New World screwworm.

Where you're going

Scores are for a December–April trip.

beach

Puerto Viejo, Playa Cocles & Manzanillo

Disease risk ElevatedBite nuisance Annoying

Sand flies on the beach at dawn and dusk are the steady complaint, and mosquitoes tend to pick up after about 5 pm. Inside the CDC's malaria listing for Limón, outside its chikungunya map.

jungle

Cahuita & Cahuita National Park

Disease risk ElevatedBite nuisance Noticeable

The same beach sand flies as Puerto Viejo, plus a coastal trail through shaded forest that is a likely spot for day-biting mosquitoes. Put repellent on before you set off.

jungle

Tortuguero

Disease risk ElevatedBite nuisance Annoying

Canals and rainforest with a reputation for heavy mosquitoes around riverside lodges and trails. Dawn and late-afternoon canal tours and night walks overlap malaria-mosquito and sand-fly hours, so wear permethrin-treated clothes.

Our Costa Rica briefing covers the whole country, and the Arenal briefing covers the other province on the CDC's malaria list. Crossing into Panama? See Bocas del Toro.

The Caribbean coast kit

The spray covers the beach at dusk. Add the permethrin for Tortuguero.

Picaridin 20% travel sprays: odorless in the humidity, layers over sunscreen and deters sand flies as well as mosquitoes. One 3.4 oz bottle covers about a week of daily use for one person.
Permethrin 0.5% for tour clothes: treat a long-sleeved shirt, trousers and socks at home 48 hours before you fly. It goes on clothing, never on skin.

Carry-on trio → Permethrin → Full rankings

What travelers report

Paraphrased from TripAdvisor threads and linked so you can read them in full. Neither gives a year, so read them as the general picture.

Puerto Viejo de Talamanca / Cahuita · dawn and dusk
Posters said sand fly bites land mostly on the legs, feet and ankles on the beach at dusk or early morning. Often one person in a group reacts while the others are untouched. They advised DEET or picaridin, showering after the beach and skipping the beach at dusk. TripAdvisor ↗
Tortuguero
Experiences varied widely. One traveler in long sleeves and heavy DEET reported more than 100 bites at a riverside lodge, worst on the jungle trails behind it, while others got only a handful in a month. A lodge owner said September and October have the fewest mosquitoes. TripAdvisor ↗

One rule outlasts the trip. Any fever during or after the trip means a doctor visit, and you tell the doctor you were in Limón, Costa Rica. Dengue usually shows up within two weeks; malaria can take longer.

Traveler questions

Do I need malaria pills for Puerto Viejo or Tortuguero?

Puerto Viejo, Cahuita and Tortuguero are in Limón, one of the two provinces where the CDC says malaria is present and lists prevention medicines. The other is Alajuela, home to Arenal. Whether that adds up to a prescription for your trip is a call for a travel clinic, made with your exact route and nights, 4–6 weeks before departure. Malaria mosquitoes bite from dusk to dawn, so repellent at sunset and a screened or air-conditioned room help either way.

Is the Caribbean coast inside the chikungunya notice?

Not on the map. The CDC's Level 2 notice describes an outbreak in northwest Costa Rica, and its map leaves Limón province unshaded, Tortuguero included. PAHO counted 2 of Costa Rica's 539 lab-confirmed 2026 cases in Limón by mid-September. Guanacaste, Alajuela and Heredia are inside the map, so if your route includes them, raise the vaccine with a travel clinic, and check the map again before you fly.

What are the itchy bites from the beach in Puerto Viejo?

Most likely sand flies, the tiny biting midges Americans call no-see-ums. They bite feet, ankles and legs on the sand at dusk and in the early morning and are grounded by a breeze. Spray your lower legs before a late-afternoon beach session, shower after the beach and wear light trousers for dinner.

Is Tortuguero buggy?

It has a reputation for it, especially around riverside lodges and on the trails behind them. Canal tours usually leave at dawn and in the late afternoon, when mosquitoes are active along shaded banks, and night walks and turtle tours put you outside during malaria-mosquito and sand-fly hours. Wear permethrin-treated long sleeves, trousers and socks, put fresh repellent on exposed skin and sleep in a screened room or under the lodge's net.

Sources

Health authorities, surveillance reports and news coverage of official bulletins used for this briefing, last checked October 2026. Traveler reports are linked where they appear. This page summarizes public-health guidance and is not medical advice.

Costa Rica's Caribbean coast bites the most, and malaria is the travel-clinic question.