Tanzania's malaria line is 5,900 feet. Nearly every trip goes below it.

A typical Tanzania trip pairs a Northern Circuit safari through Tarangire, the Ngorongoro Crater and the Serengeti with a few days on Zanzibar, and sometimes a Kilimanjaro climb as well. The mountain and the crater rim sound as if they should be above the malaria question, and parts of them are. Nearly every itinerary still spends nights below the CDC's line, which makes the travel clinic the first booking after the flights.

The 5,900-foot line

The CDC's Tanzania page, which covers Tanzania including Zanzibar, recommends malaria prevention medicine for all areas below 5,900 feet (1,800 m). The parasite is mainly Plasmodium falciparum, resistant to chloroquine, and the CDC lists four prevention medicines: atovaquone-proguanil, doxycycline, mefloquine and tafenoquine.

Below the line sit Zanzibar, Dar es Salaam, Tarangire, Lake Manyara, most of the Serengeti, Arusha and Moshi. The Ngorongoro Crater rim and its lodges rise above it, but the road in through Karatu and the rest of the circuit stay below, so the recommendation applies to the trip as a whole.

Whatever the clinic decides, malaria mosquitoes bite from dusk to dawn. Repellent at sunset, long sleeves after dark, and a net or a screened, air-conditioned room overnight cover most of that exposure.

Kilimanjaro starts low

It's tempting to think altitude takes care of malaria on a Kilimanjaro trip. On the upper mountain it does. The climb starts and ends in Moshi or Arusha, though, and both towns are below the line, so the CDC's recommendation covers the nights before and after the trek and any safari or beach days you add. Give the clinic the climb dates with the rest, and keep the dusk routine going in town. Bugs tend to be scarce on the trail itself.

Yellow fever: rarely recommended, sometimes required

The CDC says yellow fever vaccine is generally not recommended for travel to Tanzania, Zanzibar included, and it is not required for direct travel from the US. The rule to watch applies on arrival. Tanzania requires proof of vaccination from travelers 1 year or older arriving from a country with yellow fever risk, including airport transits or layovers of more than 12 hours in such a country.

A Kenya-and-Tanzania safari is the classic case to check. The CDC recommends the vaccine for most of Kenya, so if you're crossing from Kenya, confirm before you fly whether a certificate will be checked; our Kenya briefing lists which Kenyan trips fall under that advice. A long connection through a risk country is the other, so bring your routing to the clinic.

Separately, CDC's Level 2 Global Polio notice, updated September 23, 2026, lists Tanzania, including Zanzibar, and CDC advises being up to date on polio vaccine before international travel.

Tsetse flies: the safari nuisance

Tsetse flies are a frequent complaint on the Northern Circuit. They bite in the daytime, the bite is painful, and they are known for following moving vehicles and homing in on dark blue and black. People who have done the circuit describe midday as the peak.

Tarangire has the strongest tsetse reputation of the main parks, the Serengeti's wooded areas have patches of their own, and the cool Ngorongoro Crater has a reputation for few.

The CDC's Tanzania page lists African sleeping sickness, which tsetse flies spread, and its advice is to avoid bug bites. Wear neutral-colored long sleeves and trousers on game drives, leave dark blue and black at home, and ask your guide to steer around known tsetse pockets, especially in Tarangire.

The same page lists leishmaniasis, spread by tiny sand flies that bite from dusk to dawn, which the evening routine covers. It also lists African tick-bite fever and Crimean-Congo hemorrhagic fever from ticks, a reason for long trousers on walks in long grass, and Rift Valley fever, spread by livestock contact and mosquito bites.

Zanzibar beach evenings

Zanzibar's mosquito reputation swings widely, and the difference tends to come down to the season and to whether people sit out at dusk without repellent. The malaria mosquito starts work at dusk, the hour of sunset drinks at Nungwi or Paje, and keeps going until dawn. The Aedes mosquito that carries dengue bites in daylight, with peaks after sunrise and before sunset, on the island and in Dar es Salaam.

Dengue in Tanzania comes in periodic outbreaks centered on Dar es Salaam, including a large epidemic in 2019, and a 2024 study found the virus circulating in the city between outbreaks. On February 25, 2026, the health ministry's chief medical officer warned, as reported in the Tanzanian press, that heavy rains had raised dengue risk. Tanzania is not on the CDC's Global Dengue list, last reviewed October 2, 2026, and WHO's Africa bulletin for October 5–11, 2026 lists no dengue event there.

The beaches also have a reputation for sand flies and ants at ankle level. Repellent on feet, ankles and calves before a sunset walk covers the beach biters and the evening's first mosquitoes; our sand fly guide explains why breeze and timing matter.

Where you're going

The disease score tracks CDC's malaria line; the bite score moves between tsetse parks, cool highlands and the coast.

Continuing on to South Africa? Our South Africa briefing covers that leg.

When to go

Americans visit Tanzania in every month. The long dry season, June to October, and the drier spell of January and February tend to be the lighter months for mosquitoes. The long rains, roughly March to May, and the short rains, roughly November and December, tend to bring more, and April and May tend to be the hardest months on Zanzibar and the coast. The CDC's malaria advice applies in every month.

What travelers report

Paraphrased from forum threads and linked so you can read them in full. None carries a date, and individual trips vary with the season, the rain and where you stay.

• Northern Circuit parks (Tarangire, Serengeti, Ngorongoro, Arusha NP)

  Posters ranked parks by tsetse: Tarangire was the most consistent hotspot with many pockets in bushy areas, the Serengeti was patchy (few at Seronera, more around Lobo and Kusini), and Ngorongoro Crater and Arusha National Park had few or none. They disagreed on which season is worst and advised avoiding dark blue and black clothing. TripAdvisor ↗

• Nungwi, Zanzibar

  A poster saw no mosquitoes during a 3.5-day stay in Nungwi but noted that the season may matter. TripAdvisor ↗

• Nungwi, Zanzibar

  A traveler described waking up with about 200 bites after sitting on a balcony at dusk without repellent. TripAdvisor ↗

One more rule outlasts the trip. Any fever during or after your trip means a doctor visit, and you tell them you were in Tanzania, including the parks and Zanzibar. With malaria in the picture, the rule holds for a full year after you get home. That one sentence is what gets you the right test quickly.

Traveler questions