Colombo was among the hardest-hit districts in Sri Lanka's dengue year. The mosquitoes bite by day.
- CDC Level 1 Global dengue (Sri Lanka listed)
More than half of Sri Lanka's 100,127 dengue cases through September 27, 2026 were in the Western Province, with Gampaha and Colombo the most affected districts. There is no malaria, so the job in Colombo is a daytime repellent habit.
Yes, and in 2026 they mattered. Colombo was among the hardest-hit districts in Sri Lanka's dengue epidemic, and the mosquito that spreads dengue bites in daylight, in the city's gardens, markets and building sites. There is no malaria. Our Sri Lanka briefing covers the rest of the island.
Colombo's dengue year
Sri Lanka's National Dengue Control Unit counted 100,127 cases by September 27, 2026, and 52.5% of them were in the Western Province, which takes in Colombo and Gampaha districts, according to figures reported by the European Centre for Disease Prevention and Control. Colombo district led the country in January, well before the monsoon, and was still the worst-affected district in early July, according to press reports of the unit's data. By August, neighboring Gampaha had overtaken it.
Nationally, the epidemic peaked in July with 29,964 cases and fell to 4,637 in September 1–27. Even then, weekly cases in mid-September were about 90% above the same week of 2025, the World Health Organization reported. Sri Lanka is on the CDC's global dengue list, a Level 1 notice for countries with higher-than-usual case numbers.
Colombo was also the center of the 2025 chikungunya outbreak. It was one of three sentinel sites, with Gampaha and Kandy, that confirmed 151 cases from January to mid-March that year, and by the end of August 2025 Colombo District alone had a third of the outbreak's cases, WHO reported.
Where the day-biters wait
Dengue and chikungunya both spread through Aedes mosquitoes, which bite by day with peaks after sunrise and in the late afternoon. In a dense city they tend to breed in containers, gutters, roof drains and building sites and to rest in the shade. A morning in Fort and the Pettah markets is spent in their hours. The gardens and lakeside paths around Beira Lake, Gangaramaya Temple and Viharamahadevi Park are the sheltered kind of place they like. The seafront at Galle Face Green and the hotels at Mount Lavinia tend to catch a sea breeze, which helps.
Put repellent on over sunscreen before breakfast, again after a sweaty walk and again before the late afternoon. Choose an air-conditioned or screened room, keep balcony doors shut, and in a guesthouse check that the net has no holes. Our dengue & Zika routine has the full schedule. Treat a first or last night near the airport the same way. Bandaranaike International Airport and the Negombo beach hotels are in Gampaha district, the worst-hit district by August.
No malaria, few vaccine questions
WHO certified Sri Lanka malaria-free in 2016, and the CDC recommends no malaria medicine for the country. A short city stay also falls outside the CDC's Japanese encephalitis advice, which calls the vaccine "Not recommended for travelers planning short-term travel to urban areas." Yellow fever vaccine isn't needed when you fly from the US. The CDC lists Zika for Sri Lanka, so pregnant travelers should talk to a provider first. Leishmaniasis, spread by sand flies, is concentrated in the dry zone and the south rather than the Western Province.
When to go
Roughly February to April tends to be the easiest stretch. May to August, under the southwest monsoon and around the 2026 national peak, is the hardest, and October and November tend to bring more rain. January is no safe bet either, since Colombo district led the country's count that month. No month is dengue-free.
Where you're going
Fort & the Pettah markets
The old core and the bazaar lanes, inside the Colombo Municipal Council area, where a special dengue control program began in late February 2026. A walk here is a daytime outing in dengue-mosquito hours, so repellent goes on before you set out.
Galle Face Green & the seafront hotels
The sea breeze tends to help on the promenade and in sea-facing rooms. The sunset crowd gathers in the late-afternoon biting peak, so refresh your repellent before you walk over.
Beira Lake, Gangaramaya & Viharamahadevi Park
Shaded, watered grounds of the kind where day-biting mosquitoes rest. Cover your ankles for temple visits, where shoes come off, and reapply in the afternoon.
Mount Lavinia
Beach hotels and seafood restaurants just south of the city, still in Colombo district. Breezy on the sand, likely buggier in hotel gardens and at beach dinners after dark.
Heading on? Our Kandy and Cultural Triangle briefing covers Sigiriya's sand flies, and our Galle and south coast briefing covers Unawatuna, Mirissa and Yala.
The Colombo kit
- Picaridin 20% travel sprays: odorless in the humidity, layers over sunscreen and is easy to reapply on a city walk. One 3.4 oz bottle covers about a week of daily use for one person.
- A full-size backup in the checked bag for a two-week island loop or a family, so you're not relying on whatever the local pharmacy stocks.
What travelers report
Paraphrased from a TripAdvisor forum thread and linked so you can read it in full. It isn't dated, it looks several years old and it's about dengue risk rather than bite numbers, so use the figures above for this year.
- Colombo (thread about a Hikkaduwa family trip)
A family planning a trip asked about dengue. One reply said Colombo, being built up, is where visitors need to be most careful because dengue is far more common there, cited a figure of nearly 42% of 2017 cases from the Western Province, and advised going straight to a hospital for a blood test with any symptoms; other replies disagreed about whether tourists are affected differently. TripAdvisor ↗
Any fever during or within two weeks after your trip means a doctor visit, and you tell them you were in Sri Lanka. Our after-the-bites guide covers dengue testing and warning signs.
Traveler questions
Is dengue still bad in Colombo?
It's past the peak and still above normal. Nationally, cases peaked in July 2026 at 29,964 and fell to 4,637 in September 1–27, but in mid-September weekly cases were still about 90% above the same week of 2025, the World Health Organization reported. Colombo district was the worst-affected district in January and again in early July, and neighboring Gampaha had overtaken it by August, according to press reports of National Dengue Control Unit data. Put repellent on in the morning, after sweating and before the late afternoon.
Do I need malaria pills for Colombo?
No. The CDC recommends no malaria medicine for Sri Lanka. WHO certified the country malaria-free on September 5, 2016, and there have been no locally acquired cases since October 2012. WHO also says imported cases and the mosquitoes still found across the island keep a risk of reintroduction, so any fever after the trip still means a doctor visit.
Do I need vaccines for a few days in Colombo?
For Japanese encephalitis, the CDC says the vaccine is "Not recommended for travelers planning short-term travel to urban areas," which fits a city stay. It recommends it for a month or more in areas with the disease and says to consider it for shorter trips with rural stays, hiking or camping, so bring the rest of your Sri Lanka route to a travel clinic 4–6 weeks ahead if it includes those. For chikungunya, the CDC says vaccination "is generally not recommended." Yellow fever vaccine isn't needed when you fly from the US.
Is it safe to visit Colombo while pregnant?
The CDC lists Zika among the bug-borne diseases in Sri Lanka. If you're pregnant or planning a pregnancy, talk to a healthcare provider before you book, and keep the daytime repellent habit strict, since dengue is the bigger everyday risk in the city.
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.
- CDC destination page for travelers
- CDC Travel Health Notice
- European Centre for Disease Prevention and Control
- World Health Organization
- newsfirst.lk
- election.newsfirst.lk
- newsfirst.lk
- english.newsfirst.lk
- counterpoint.lk
- World Health Organization
- Peer-reviewed study (PubMed Central)
- World Health Organization
- World Health Organization
- World Health Organization
- European Centre for Disease Prevention and Control
- World Health Organization