Mosquitoes in Mombasa & Diani: Malaria, Dengue & Beach Sand Flies (2026)

Q: Do I need malaria pills for Mombasa or Diani?

The CDC recommends malaria prevention medicine for all areas of Kenya below 8,200 feet (2,500 m), game parks included, with an exception only for the highly urbanized center of Nairobi. The coast is covered, Mombasa and Diani included. The CDC lists atovaquone-proguanil, doxycycline, mefloquine and tafenoquine; which one fits you is a call for a travel clinic, made 4–6 weeks before departure. Our malaria-zone checklist covers the rest.

Q: Do I need a yellow fever vaccine for a Diani beach trip?

Generally not, if the trip is limited to the coast and Nairobi. The CDC recommends the vaccine for travelers 9 months and older but lists travel limited to Nairobi or the former Coast Province counties other than Taita-Taveta, including Mombasa and Kwale, where Diani is, as exceptions. Adding Tsavo, which lies in Taita-Taveta, or a Mara safari brings the recommendation back. Kenya doesn't require the vaccine for direct arrivals from the US.

Q: When is dengue season on the Kenyan coast?

Kenya's health ministry, as reported in the Kenyan press in 2026, puts the coastal peak at April to June, when the long rains fall. Dengue circulates outside those months too: in a 2019–2022 study, 43.9% of participants in Ukunda, behind Diani Beach, had dengue antibodies. The mosquito bites by day, so repellent goes on over sunscreen in every month.

Q: What are the itchy bites on Diani Beach?

Travelers blame sand flies, tiny beach biters that leave delayed, itchy welts on feet, ankles and calves around dawn and dusk. Cover up or reapply repellent on your lower legs at those hours. Our sand fly guide explains how they behave.

The CDC recommends malaria medicine for the whole coast, and Kenya's health ministry calls Mombasa, Kilifi and Kwale a major dengue zone, with cases peaking April to June. On the beach the complaint is sand flies, and indoors it's room mosquitoes.

Yes, and on the coast they work both shifts. Malaria mosquitoes bite from dusk to dawn, and the CDC recommends prevention medicine for Mombasa, Diani and the rest of the coast. By day, the Aedes mosquito spreads dengue and chikungunya, and Kenya is on the CDC's Global Dengue list.

Disease risk ElevatedCDC recommends malaria medicine for the whole coast, Kenya is on CDC's global dengue list, and Mombasa had a chikungunya outbreak in mid-2025.

Bite nuisance AnnoyingRoom mosquitoes at night and sand flies on the beach at dawn and dusk are the usual complaints; boat days tend to be lighter.

CirculatingMalaria (whole coast)Dengue (April–June peak)No yellow fever vaccine for a coast-only tripNo chikungunya reported in 2026

CDC noticesLevel 1 · Global dengue (Kenya listed) · CDC

Travel clinicCDC recommends malaria medicine for all of Kenya below 8,200 ft (2,500 m) except central Nairobi, which covers Mombasa, Diani and the rest of the coast. Yellow fever vaccine is generally not recommended for travel limited to Nairobi and the former Coast Province counties other than Taita-Taveta, Mombasa and Kwale included; adding Tsavo or a safari park brings the recommendation back.

When to goThe drier months, roughly January–February and June–October, tend to be lighter. April–June is the coastal dengue peak, on top of the long rains, and the short rains, roughly October–December, tend to bring mosquitoes back. CDC's malaria advice applies in every month.

Data checkedOctober 2026 · sources

The CDC's two answers for a coast trip

What CDC says: its Kenya page gives the malaria areas as "All areas (including game parks) <2,500 m (<8,200 ft) elevation; rare cases in the highly urbanized central part of the city of Nairobi (the capital)" and lists "Atovaquone-proguanil, doxycycline, mefloquine, tafenoquine." For yellow fever, the vaccine "is generally not recommended for travel limited to" Nairobi, three northeastern counties "or the counties (except Taita-Taveta) of the former Coast Province (Kilifi, including the city of Malindi; Kwale; Lamu; Mombasa, including the city of Mombasa; Tana River)." What we suggest you do with this: book a travel-medicine appointment 4–6 weeks before departure with your full route. Diani is in Kwale, so a Nairobi-and-coast trip sits on the yellow fever exception list, while Tsavo or a Mara safari brings the recommendation back.

Kenya also has a CDC Level 1 notice, posted October 19, 2026, for Ebola cases in Nairobi; Ebola isn't spread by insects, and the notice lists the usual precautions.

Dengue and chikungunya

Kenya's health ministry, as reported in the Kenyan press in 2026, called the coast, especially Mombasa, Kilifi and Kwale, a major dengue transmission zone, with cases peaking April to June, and press reports of ministry figures put Mombasa County among the highest early-2026 counts in the country. The World Health Organization's late-July 2026 situation report tracked an active outbreak only in the northeast, and its Africa bulletin for October 5–11, 2026 lists no dengue event for Kenya. In a 2019–2022 study, 43.9% of participants in Ukunda, the town behind Diani Beach, had dengue antibodies, against 6% in Kisumu.

Chikungunya travels with the same mosquito. An outbreak confirmed in Mombasa County on June 8, 2025 reached 614 cases, 97 of them laboratory-confirmed, with no deaths, and WHO reported no further cases after early July 2025. The European Centre for Disease Prevention and Control's September 2026 overview lists no chikungunya cases in Kenya.

Both viruses ride the day-biting Aedes, so repellent goes on over sunscreen in the morning, again after swimming and again before sunset, when the malaria hours begin.

Beach sand flies, room mosquitoes and day trips

On the sand, the complaint is sand flies, which leave delayed, itchy welts on ankles and calves around dawn and dusk. Indoors, it's room mosquitoes, and nets and screens vary between hotels and rentals. Sleep under an intact, tucked-in net or in a screened, air-conditioned room, and bring a travel net if your rental has none.

Tsetse flies occur in Shimba Hills National Reserve. They bite by day, so wear neutral long sleeves and keep the vehicle windows up where they gather. Dhow and snorkel days at Wasini and Kisite-Mpunguti tend to be light on biters, since most of the day is at sea.

When to go

The drier months, roughly January–February and June–October, tend to be lighter. April to June is the coastal dengue peak, overlapping the long rains. The short rains, roughly October to December, tend to bring mosquitoes back. The CDC's malaria advice applies in every month.

Where you're going

beach

Diani Beach & Ukunda

Disease risk ElevatedBite nuisance Annoying

Beach sand flies with delayed, itchy bites and room mosquitoes are the review complaints. Cover ankles at dawn and dusk, and check the net over your bed.

city

Mombasa Old Town, Nyali & Bamburi

Disease risk ElevatedBite nuisance Noticeable

Mombasa County had a chikungunya outbreak in mid-2025, and the day-biting dengue mosquito is the town biter. Repellent over sunscreen before a Fort Jesus or Old Town walk.

safari

Shimba Hills

Disease risk ElevatedBite nuisance Annoying

Tsetse flies occur here and bite by day. Neutral long sleeves, repellent on exposed skin and windows up where the flies gather.

island

Wasini & Kisite-Mpunguti

Disease risk ElevatedBite nuisance Occasional

Dhow and snorkel days are mostly at sea and tend to be light on biters. Repellent for lunch and the walk on Wasini; malaria advice still applies to the trip.

Our Kenya briefing covers Nairobi, Lamu and the parks, and the Maasai Mara briefing covers a migration safari.

The Kenya coast kit

One spray for both shifts, plus a net for rentals.

Picaridin 20% travel sprays: odorless in the heat, layers over sunscreen and covers ankles at sand fly hour. One 3.4 oz bottle covers about a week for one person.
A full-size backup in the checked bag for a two-week beach stay or a family.
A travel bed net if your rental has no screens or nets.

Carry-on trio → 8 oz backup → Full rankings

What travelers report

Paraphrased from Diani traveler posts and linked so you can read them in full. Neither is dated, and the season and your room change the picture.

Diani Beach (Pinewood)
A traveler asked for help with sand fly bites at Pinewood that showed up delayed and itchy and did not respond to DEET. TripAdvisor ↗
Brightstar Apartments, Diani
A guest asked for the room to be sprayed for mosquitoes, was told no repellent was available, and was bitten during the night. TripAdvisor ↗

One rule outlasts the trip. Any fever during the trip or in the year after it means a doctor visit and a malaria test, and you tell the doctor you were on the Kenyan coast.

Traveler questions

Do I need malaria pills for Mombasa or Diani?