The Whitsundays' worst bites come from midges on the sand. Ross River virus is the one to know.

Yes, though on a December–April trip the bites most visitors notice come from biting midges, which Queenslanders call sandflies, on Whitehaven Beach and the island shores, and from March flies on summer beaches and boats. The mosquito-borne disease to know is Ross River virus, endemic on this coast and active in the wet season. There is no malaria, and the CDC has no travel notice for Australia. Our Australia briefing covers the rest of the country.

Ross River and Barmah Forest season

Ross River virus is on the CDC's list for Australia, and Queensland carries much of the load. The state recorded 43,699 notifications from 2001 to 2020, about 48% of the national total and an average of 51 cases per 100,000 people a year, according to a 2026 review in Clinical Microbiology Reviews. A study of those two decades named Mackay, south of the islands, among Queensland's northern coastal areas with both high case totals and high incidence.

Mackay's own numbers are modest. In the city, cases from 2007 to 2020 came sporadically from late spring to early autumn, with weekly peaks of around 5 to 10 cases and no obvious outbreak in 13 years, a 2023 study found. In a 2013–14 survey, 90% of sampled horses in the Mackay-Whitsunday region carried Ross River antibodies. In February 2024, Queensland Health warned of very high Ross River levels in mosquitoes in council areas from Mackay south, according to press reports.

Barmah Forest virus, also spread by mosquitoes, is present too, and the same horse survey found antibodies to it on 15% of sampled properties in northern Queensland. The mosquitoes behind both build after wet-season rain, so add repellent at dawn, at dusk and after rain to the beach routine.

The CDC also lists dengue for Australia, without naming Queensland, and we know of no local dengue in the Whitsundays; the FAQ below has the details. The CDC's Japanese encephalitis areas are far from here.

Midges on the sand, March flies on the boats

Whitehaven Beach draws more bite complaints than anywhere else in the islands. Biting midges are the main culprit, tiny flies that go for ankles and lower legs, worst around dusk and in still air. Queensland's coastal midges breed in intertidal sand and mud and disperse from there, so spraying adults rarely works, a study at Hervey Bay farther south found. They're weak fliers, so a breeze helps, and mangrove and creek edges around Airlie Beach tend to be midge country too. Our sand fly guide explains how they behave.

March flies, large biting flies, turn up on summer beaches and boats, and a tour operator describes their season as generally brief. Put repellent on feet, ankles, calves and other bare skin before you step off the boat at Whitehaven or Hill Inlet, before hikes such as Passage Peak and before dusk on the Airlie waterfront, and reapply after swimming. Out on sailing boats and reef pontoons there tends to be little to bite. Try not to scratch; for the itch, the CDC suggests hydrocortisone cream or calamine lotion.

Marine stingers, box and Irukandji jellyfish, are a separate hazard in roughly the same months, so follow local beach advice.

When to go

December to April is the hot, humid wet season, with summer storms, and the months for Ross River virus, midges and March flies. From June to October, the dry season, you're outside the window when Mackay's Ross River cases occur, and bites tend to ease.

Where you're going

Heading north too? Our Cairns briefing covers Port Douglas and the Daintree.

What travelers report

Paraphrased from TripAdvisor reviews and forum threads and linked so you can read them in full. None is dated to a year, and wind, tide and time of day change the picture from one beach stop to the next.

• Whitehaven Beach, Whitsundays

  A reviewer warned of thousands of sand flies on the beach and counted 54 bites after sunbathing. TripAdvisor ↗

• Cruise Whitsundays boat tour, Airlie Beach · summer

  A reviewer complained of swarms of March flies on a boat tour. The operator replied that March flies are seasonal, appear in summer, and have a generally brief season in the Whitsundays. TripAdvisor ↗

• Whitehaven Beach (helicopter tour stop) · December

  A December helicopter passenger found the biting flies heavy during the beach stop and felt the operator had given no warning. TripAdvisor ↗

• Passage Peak, Hamilton Island

  A hiker warned that sandflies chased and bit them on the Passage Peak walk in the morning. TripAdvisor ↗

• Long Island resort · summer

  A guest said sandfly and midge bites left scars for months. The management reply said sandflies and midges are present in the summer months, advised not scratching and a cold shower, and pointed to the itch cream provided in the villas. TripAdvisor ↗

• Whitehaven Beach

  A visitor asked about mystery bites; a reply blamed local midges, said they are most active around dusk and common at Whitehaven, and suggested calamine lotion or tea tree oil for the itch. 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