Iceland had no mosquitoes. Until October 2025

For all of its recorded history, Iceland had no mosquitoes. The country has lakes, wetlands and long summer days, exactly the kind of place mosquitoes usually thrive, yet alongside Antarctica it was one of the only regions on the planet without a single record of one. That changed in October 2025, when three mosquitoes turned up on a farm north of Reykjavík.

The find was confirmed by the Natural Science Institute of Iceland. Antarctica is now the only place in the world believed to be mosquito-free.

A ribbon soaked in red wine

The mosquitoes were found by Björn Hjaltason, an insect enthusiast, on a farm in Kjós, north of Reykjavík. He hangs ribbons soaked in red wine to attract moths. At dusk on October 16, he spotted a strange fly on one of them. “I immediately suspected what was going on and quickly collected the fly,” he told the Icelandic broadcaster RÚV. It was a female.

He later caught two more and handed all three to the authorities. Tests showed they were two females and one male of the species Culiseta annulata, and the institute announced the discovery on October 21.

Why they never made it before

Mosquitoes had been found on planes landing in Iceland before, and none of them ever started a population. What kept them out, as far as scientists can tell, was the climate itself.

Icelandic winters are milder than the latitude suggests, but they’re unstable. According to Science News, the island freezes and thaws several times a year. Those swings can threaten adult mosquitoes that leave their shelter during a thaw and get caught by the next cold snap, as well as species that spend the winter as eggs or larvae. Some species are sensitive enough to those swings that they never get established.

What changed

Two things, researchers say. The first is transport: the Icelandic institute believes the mosquitoes hitched a ride in freight, as trade and travel keep growing. The second is climate. The Arctic is warming roughly four times as fast as the global average, according to Science News, and Iceland saw record heat in 2025.

The species that arrived helps too. Culiseta annulata is a large mosquito, common across Europe, including Sweden and Finland, and used to the cold. Adults sit out the winter in basements, sheds and caves, which may shield them from the swings that stopped other species.

Whether it will stay is still unknown. In November 2025, scientists said it was too early to tell whether those few individuals would survive the winter and breed. The fact that both males and females were found suggests they could. But as ecologist Kelsey Lyberger of Arizona State University pointed out, luck plays a part too: if those few individuals don’t survive or don’t breed, the population simply never forms.

Should anyone worry?

Not much, for now. Culiseta annulata bites, but according to the Icelandic institute it doesn’t carry known infections where it lives. A 2017 study described it as a biting nuisance rather than a deadly foe. That distinction matters: there are more than 3,000 mosquito species worldwide, and some spread serious diseases such as malaria, dengue and West Nile virus. According to the Icelandic institute, the mosquito is just one of several new insect species found in the country in recent years, as the climate warms and international transport grows.

What catches scientists’ attention is the signal. For entomologist Jessica Ware of the American Museum of Natural History, the fact that mosquitoes never showed up in the whole history of human travel to the island, and now have, suggests the shift is climate-driven. Other insects, such as dragonflies that prey on mosquitoes, may follow the same path.

If you’re visiting

• Don’t change your plans. Sightings are still rare, and this species carries no known diseases.
• Don’t expect to run into them. The 2025 records were three insects on a single farm.
• Curious? Follow the Icelandic institute. It confirms every new record in the country.

Iceland is already a place where the sun and the clock don’t line up, as the post on why the country hasn’t changed its clocks since 1968 explains. Now it has lost one of its most famous quirks as well.

Sources

• Iceland reports the presence of mosquitoes for the first time, as climate warms, NPR, 2025: the discovery, Björn Hjaltason’s account to RÚV, the institute’s confirmation, arrival by freight, mosquitoes on planes and the 2017 study.
• Mosquitoes infiltrated Iceland. Will they survive the winter?, Science News, 2025: the announcement date, repeated freezing and thawing, Arctic warming, 2025 heat, the species’ winter habits and Jessica Ware’s view.