Manuel Antonio's mosquitoes stay mostly in the forest, and dengue is the one to plan around.

Yes, mostly on the national park's shaded forest trails, with fewer on the open beach. Dengue is the one to plan around. The health region that includes Quepos has had some of Costa Rica's highest dengue rates in 2026, and the map for the CDC's chikungunya notice shades the coast around Quepos. Both viruses spread through a mosquito that bites by day.

Dengue and the chikungunya map

Costa Rica's dengue count rose sharply from May and is running above 2025, with DENV-3 the main type, according to the Pan American Health Organization. Costa Rica is also on the CDC's global dengue list. By August, the health ministry's Pacífico Central region, which covers Quepos, Parrita and Jacó, had the highest rate for its population in the country, according to press coverage of ministry data.

The CDC's Level 2 chikungunya notice, last reviewed July 30, 2026, describes an outbreak in northwest Costa Rica, and the CDC's map for the notice shades Puntarenas' central Pacific coast around Quepos, which takes in Jacó, Parrita and Manuel Antonio. Local transmission there has been light so far. PAHO counted 29 of Costa Rica's 539 lab-confirmed 2026 cases in Puntarenas province by mid-September. The CDC says "Vaccination is recommended for travelers who are visiting an area with a chikungunya outbreak," and it advises pregnant travelers to reconsider travel to the affected areas, particularly close to delivery.

Forest trails, surf and mangroves

The park's mosquitoes tend to stay in the shaded forest behind the beaches, and the open sand is usually milder. Morning visits timed for the park's opening overlap the dengue mosquito's first daily peak, so put repellent on over sunscreen before you go in, reapply after swimming and wear light long sleeves on the trails. Lowland humidity means more bites here than in the highlands.

The small stings some swimmers feel in the water are blamed on sea lice or tiny jellyfish. They aren't insect bites, and repellent won't prevent them. Biting midges, the dawn-and-dusk beach complaint in Guanacaste, come up far less here. The Damas Island mangroves north of Quepos are a likely spot for dusk mosquitoes, so wear long sleeves on a late boat tour.

The dry season helps

December to April is the dry season on the central Pacific coast, and residents report very few mosquitoes on the Pacific side from January to early April. Dengue was still running above 2025 in September, though, so early December may still see transmission, and in October 2026 PAHO warned of outbreaks outside the usual seasons as El Niño strengthens. Check whether the chikungunya notice is still active before you fly.

Where you're going

Scores are for a December–April trip.

The Costa Rica briefing covers the whole loop, and our Arenal and Guanacaste briefings cover the volcano and the northern beaches.

What travelers report

Paraphrased from TripAdvisor threads and linked so you can read them in full. None gives a year or a month, so read them as the general picture.

• Manuel Antonio

  A traveler got only a handful of mosquito bites on a six-day Manuel Antonio trip and then came down with dengue. Forum members stressed using repellent, noting that dengue mosquitoes bite in the daytime and are most active around dusk. TripAdvisor ↗

• Manuel Antonio National Park

  In a thread titled 'Mud, Mosquitoes and Monkeys', a poster said mosquitoes are more common in the shaded forest than on the beach. TripAdvisor ↗

• Manuel Antonio beaches

  Visitors described small, painful stings while swimming. Posters put them down to sea lice or tiny jellyfish and said they are usually minor, though they can hurt more for children. TripAdvisor ↗

One rule outlasts the trip. Any fever or joint pain during or after the trip means a doctor visit, and you tell the doctor you were in Quepos, Costa Rica. If you were bitten, bitten in a dengue zone covers what to watch for.

Traveler questions