Are there mosquitoes in Cairns? Yes, and many of them now block dengue.

Yes, though a June–October trip lands in the dry season, when mosquitoes around Cairns tend to be few. The dengue mosquito still lives in town, but in the treated suburbs of Cairns and Port Douglas it now mostly carries Wolbachia, a bacterium that blocks the virus. The bites people complain about are from biting midges at dusk.

The mosquitoes that stopped carrying dengue

Far North Queensland used to have large dengue outbreaks. From 2000 to 2019, Queensland Health recorded 2,086 locally acquired cases in Cairns and the surrounding council areas, with big outbreaks in 2003 (450 local cases) and 2009 (776). From 2011 to 2017, Wolbachia-carrying Aedes aegypti were released across Cairns, the northern beaches and Douglas Shire, which takes in Port Douglas, Mossman and Mossman Gorge. In the eight years after the first releases, only four local cases turned up in the treated areas, and the evaluation, published in Gates Open Research in 2019, estimated a 96% reduction in dengue.

The effect has held. In May 2025 the regional health service reported the Cairns region's first locally acquired case in years, said every other case since 2018 had been picked up overseas or interstate and called the public risk low because of the high Wolbachia coverage. We know of no local case in Cairns in 2026. Townsville, farther south, shows the protection has limits. It had its first sustained local outbreak in the 2024/25 wet season, 16 cases in two inner-city suburbs despite Wolbachia, according to a 2026 study.

Ross River virus is the other one to know. It is endemic, listed by the CDC for Australia, and builds through the wet season to a late-summer peak, so a dry-season trip sits at the low end. There is no malaria, the CDC's Japanese encephalitis areas (the Murray River and the Outer Torres Strait Islands) don't include Cairns, and there is no CDC notice for Australia.

Dusk midges, the Daintree and the reef

The bites that bother most visitors come from biting midges, which Queenslanders call sandflies. They are worst around dusk and in still air, and they have a reputation around Palm Cove, on Cape Tribulation's beaches and along mangrove and mudflat edges such as the Cairns Esplanade. They are weak fliers, so a breeze or a fan helps. Put repellent on feet, ankles and calves before late-afternoon beach time. Our sand fly guide explains their habits.

The Daintree sits outside the published Wolbachia release areas. It tends to be driest by October, and bites tend to come near mangroves, rivers and lakes, or when you stand still on a forest walk. Wear long sleeves and trousers there and reapply after rain. Out on the reef, boats and pontoons tend to have little to bite.

December to April changes the picture. The wet season brings storms, more mosquitoes and the Ross River peak, and it is when the region's dengue outbreaks happened: 94% of local cases from 2000 to 2019 fell between December and May. In those months, add daytime repellent to the dusk routine.

Where you're going

Heading to the Whitsundays, Sydney or the Outback too? Our Australia briefing covers the rest of the country.

What travelers report

Paraphrased from TripAdvisor threads and linked so you can read them in full. None is dated to a year, and wind, rain and where you stand change the picture from one day to the next.

• Palm Cove

  A visitor was surprised by a midgie problem at Palm Cove, and a pharmacist identified the biters as sandflies. Another poster had no bites in a 10-day stay, while a party on a Fitzroy Island day trip were all bitten. TripAdvisor ↗

• Daintree Rainforest · October

  A poster said October is usually one of the driest months, so there should be few or no mosquitoes, but still advised bringing repellent. TripAdvisor ↗

• Cape Tribulation · November

  A reply said midgies are present on the beaches even during a dry start to the wet season, and that November afternoon storms can bring more biting insects. TripAdvisor ↗

• Daintree, Atherton Tablelands and Cairns

  Posters advised long trousers and sleeves when standing still in the Daintree forest and said bites are more likely near mangroves, lakes, rivers and rainforest. TripAdvisor ↗

One rule outlasts the trip. Fever, rash or joint pain during or after your trip means a doctor visit, and you tell the doctor you were in north Queensland.

Traveler questions