Thailand's tropical rainfall and mountainous interior produce some of Southeast Asia's most spectacular waterfalls — from the accessible multi-tiered mineral pools of Erawan to the remote 200-metre cascade of Thi Lo Su on the western border. Most fall within national parks and are best visited in the cooler months following the rains, when water levels are high but trails are not dangerously slippery. Many have swimming areas and are excellent for half-day or full-day excursions from nearby cities.
Kanchanaburi Province
Best season: October–April (water levels best Sep–Nov, accessible Oct–Feb)
Seven tiers of emerald-green pools cascading through Erawan National Park. Each tier is swimmable. The lower three are most visited; the upper four require a 2–3 hour hike through forest. The mineral-rich water produces extraordinary turquoise colouring. Fish at every level will nibble dead skin from feet and legs — a natural 'fish spa' experience.
Tak Province, western border region
Best season: November–December (accessible only late Oct–early Jan)
The largest waterfall in Thailand and one of the most spectacular in Southeast Asia — nearly 200m wide and 80m tall at peak flow. Located in Umphang Wildlife Sanctuary, reachable by rough road and requiring a local permit. The journey (4WD, river crossings) is half the experience. One of Thailand's most genuinely remote major attractions.
Doi Inthanon National Park, Chiang Mai
Best season: Year-round; best July–October
A wide, accessible tiered waterfall near the entrance of Doi Inthanon National Park. Very popular with Thai visitors for picnicking and swimming. Crowded on weekends but easily combined with a summit visit to Thailand's highest peak.
Chanthaburi Province, East Thailand
Best season: Year-round; best September–December
A shrine to Queen Sunandha sits beside this forest waterfall in Namtok Phlio National Park. Clear pools with large fish (catfish over 1 metre) swimming in the shallows. Less visited than Erawan and worth the detour if you're travelling through Chanthaburi.
Chiang Mai (city edge, Doi Suthep National Park)
Best season: July–January
A small but pretty waterfall accessible from Chiang Mai's city edge — a 30-minute walk from the Nimman area into the forest. Best after heavy rains. Good for a short morning hike without committing to a full national park trip.
Khao Yai National Park
Best season: Best August–November
The 'Great Abyss Waterfall' drops 150m in three tiers through Khao Yai's dense monsoon forest. Gibbons and hornbills are often spotted nearby. One of the most dramatic waterfall experiences in Thailand. The viewpoint is accessible; getting close to the base requires a guide.