Most travelers to Cambodia do not need malaria tablets. If your trip covers the typical tourist route of Phnom Penh, Siem Reap, Angkor Wat, and the coast, there is no known malaria transmission in those areas and preventive medication is not recommended. Malaria tablets are only recommended if you plan to visit or sleep in rural, forested parts of the country.
Where Malaria Risk Exists in Cambodia
Cambodia reported just 1,384 malaria cases nationwide in 2023, a 98% decline since 2018. Only 30 of those were the more dangerous strain. The country is actively working toward full elimination by 2025, and for most visitors the risk is effectively zero.
The CDC designates three major areas as having no known malaria transmission: Phnom Penh, Siem Reap (including the main Angkor Wat temple complex), and Sihanoukville. Tonle Sap Lake also carries little to no risk. A typical visit that involves exploring temples during the day and sleeping in an air-conditioned hotel at night poses minimal danger.
Risk concentrates in deeply forested and rural areas across the rest of the country. If you’re planning jungle trekking, overnight stays in remote villages, or eco-tourism that takes you into wooded regions, particularly in provinces near the borders with Thailand, Laos, or Vietnam, malaria tablets are recommended. Over 95% of Cambodia’s malaria cases are caused by a strain called vivax, which is less life-threatening than the falciparum strain common in sub-Saharan Africa but can still cause relapses months after infection.
When Risk Is Highest
Malaria transmission in Cambodia follows the monsoon. The high season runs from June through January, peaking after the rains begin in May. Transmission drops to its lowest between February and May. If your forested trip falls during the wet season, the combination of more standing water and more mosquitoes raises your exposure.
Which Medications Are Recommended
For travelers who do need prophylaxis, the CDC recommends four options for Cambodia: atovaquone-proguanil (commonly sold as Malarone), doxycycline, primaquine, or tafenoquine. Mefloquine (Lariam) is not on the recommended list for travelers to Cambodia.
Cambodia has a complicated history with drug-resistant malaria. Western Cambodia was where the first reports of resistance to front-line treatments emerged, and by 2013 over 80% of parasites sampled in that region carried genetic mutations linked to drug resistance. Resistance patterns have shifted over the years, with parasites developing resistance to one drug class while becoming sensitive to another. This is one reason your prescribing doctor needs to know exactly where in Cambodia you’re going, not just that you’re visiting the country.
Atovaquone-proguanil and doxycycline are the two most commonly prescribed options for general travelers. Atovaquone-proguanil is taken daily, starting one to two days before entering the risk area, throughout your stay, and for seven days after leaving. Doxycycline is also taken daily but must be continued for 28 days after leaving the risk area, which makes it less convenient for short trips. Primaquine and tafenoquine require a blood test for a genetic enzyme deficiency (G6PD) before you can take them.
Pregnant Travelers and Children
If you’re pregnant and truly need to visit a forested area in Cambodia, medication options narrow considerably. Doxycycline is ruled out because it can affect fetal bone and tooth development. Atovaquone-proguanil lacks sufficient safety data for pregnancy. Primaquine and tafenoquine can cause serious blood problems in a fetus with G6PD deficiency. Mefloquine is generally considered the safest option during pregnancy for areas with drug-resistant malaria, though its use in Cambodia specifically is something to discuss with a travel medicine provider given local resistance patterns.
Children of all ages can take certain antimalarials, with doses calculated by body weight. Atovaquone-proguanil is approved for children weighing at least 5 kg (about 11 pounds). Doxycycline is only suitable for children aged 8 and older. The simplest approach for families with young children is to avoid forested risk areas altogether.
Mosquito Protection Still Matters
Whether or not you take tablets, mosquito bite prevention is the first line of defense. The mosquitoes that carry malaria bite primarily between dusk and dawn, so evenings and early mornings are the highest-risk windows.
- Repellent: Use a product containing 20% to 30% DEET or 20% icaridin on exposed skin. These concentrations provide several hours of protection per application.
- Clothing: Wear long sleeves and pants in the evening, ideally loose-fitting and light-colored. You can also treat clothes with permethrin for added protection.
- Bed nets: If your accommodation doesn’t have screened windows or air conditioning, sleep under an insecticide-treated bed net. This is particularly important in rural guesthouses.
- Room barriers: Choose rooms with intact screens on windows and doors. Air conditioning helps because it keeps mosquitoes less active and windows closed.
Recognizing Symptoms After Your Trip
Malaria symptoms typically appear 7 to 30 days after an infected mosquito bite, which means you could feel perfectly fine during your trip and develop symptoms after returning home. The vivax strain dominant in Cambodia can even lie dormant in the liver and cause illness months later.
Early symptoms look a lot like the flu: fever, chills, sweating, headache, body aches, nausea, and general fatigue. The key difference is the travel history. If you develop a fever within a year of visiting Cambodia, particularly within the first month, mention your trip when seeking medical attention. A simple blood test can confirm or rule out malaria, and early treatment is straightforward and highly effective.