Do I need to worry about malaria in every country?

No. Malaria risk is low in most major tourist centers in Thailand, Vietnam, and Bali, but Dengue fever is prevalent everywhere. Protection is necessary regardless of the specific disease risk.

Will my hotel provide a net?

Upscale hotels will not. Budget guesthouses might, but they are often torn or dirty. Always pack your own if you are staying in remote areas or beach bungalows.

Choosing effective mosquito protection for Southeast Asia

Use a combination of DEET-based repellent (30-50% concentration), permethrin-treated clothing, and a permethrin-treated mosquito net for sleeping. Avoid natural oils like citronella, as they offer almost no protection against the aggressive mosquitoes in this region.

Select the right repellent. Purchase a repellent containing 30-50% DEET. It is the gold standard for Southeast Asia. Avoid concentrations above 50% as they do not provide extra protection but increase skin irritation. For sensitive skin or plastic-heavy gear, Picaridin (20% concentration) is an effective, non-greasy alternative.
Treat your clothing. Buy a bottle of permethrin spray and treat your lightweight long-sleeve shirts and trousers before you leave home. This kills mosquitoes on contact and stays effective through 6 laundry cycles. Never apply permethrin directly to your skin.
Pack a travel-sized mosquito net. If you are staying in budget bungalows or rural areas, carry a wedge-shaped or bell-shaped net. Ensure it is permethrin-treated and has a fine enough mesh (at least 156 holes per square inch) to keep smaller insects out.
Master the application timing. Apply repellent 20 minutes after putting on sunscreen. Reapply every 4-6 hours, or more frequently if you are sweating heavily, which is constant in the humid Southeast Asian climate.

Do I need to worry about malaria in every country?: No. Malaria risk is low in most major tourist centers in Thailand, Vietnam, and Bali, but Dengue fever is prevalent everywhere. Protection is necessary regardless of the specific disease risk.
Will my hotel provide a net?: Upscale hotels will not. Budget guesthouses might, but they are often torn or dirty. Always pack your own if you are staying in remote areas or beach bungalows.