Phu Chong Na Yoi National Park

Phu Chong Na Yoi is a national park in the far southeast of Ubon Ratchathani, where Thailand meets Laos and Cambodia in the forested “Emerald Triangle.” Its centrepiece is the Huai Luang (Bak Teu) waterfall, which drops from a cliff into a wide, emerald-green basin with a sandy beach — a genuine swimming spot from roughly August to February. Entry is 200 THB for foreign adults, and the park is open daily 08:30 to 16:30.

What to see

The Huai Luang / Bak Teu waterfall is the reason most people come. A stairway of around 272 steps leads down from the visitor centre to the basin, where the water is clear and green and there’s a white-sand beach to swim from once the rainy-season flow has settled. Elsewhere in the park, Kaeng Silathip is a sandstone terrace in the stream pocked with round “giant’s kettle” potholes, Kaeng Kalao is a set of shady rapids good for a dip, and the remote Kaeng Mae Phong waterfall lets you walk behind the falling water. It’s a big, quiet park a long way from the tourist trail.

Insider Tip: Go from late rainy season into the cool months (August–February) for a full waterfall and a swimmable pool — and bring a swimsuit. The beach at the foot of Bak Teu is the highlight, but only worth it when there’s enough water.

Getting there

The park is in Na Chaluai district, on the Cambodian/Lao border southeast of Ubon Ratchathani city — remote, with little public transport, so come by car. Pay the 200 THB entry at the gate; there are food stalls near the waterfall. It pairs, loosely, with a wider Ubon border-country trip taking in the Two-Color River at Khong Chiam.

Watch out: The 272 steps down to the basin mean a stiff climb back up in the heat, and the rocks around the water are slippery. Check conditions before swimming after heavy rain, when the flow is strong.

Phu Chong Na Yoi National Park is at Na Chaluai District, Ubon Ratchathani 34280. View on Google Maps.