Tat Faek
Sixteen kilometres south of Sekong, and well-signed off Rte 11, is this wide, beautiful 5m-high waterfall where you can swim in the pool atop the falls. Do heed the red and white 'Watch Out For Biting Fish' signs around the lower pools as a diabolical puffer fish called pa pao lurks there. Stories of their fondness for attacking men's penises are only legend – told with glee by local women – but they really can take a chunk of flesh out of unlucky swimmers with their razor-sharp teeth.
Tat Hua Khon
Three kilometres south of the Tat Faek turn-off (just past the market), this waterfall is 7m tall and an impressive 100m wide. The name translates as 'Waterfall of the Heads', owing to a WWII episode in which Japanese soldiers decapitated a number of Lao soldiers and tossed their heads into the falls. Facilities, including good trails and boardwalks through the forest, kayaks (80,000K) and a restaurant, are part of the little P&S Garden resort. This is a busy place on holidays and weekends.
Sekong Provincial Historical Museum
The first floor has just a few old stones, UXO and photos from the war years. But the tribal displays of textiles and household tools (don't miss the bamboo forge for making knives) upstairs are well presented with labels in English. The focus is Katu, but Alak, Yai, Talieng, Suay and many more are covered too. It's up the road north from the tourism office.
Khamting Restaurant
Ask a local to recommend a place to eat and this is probably the only name you'll hear. It serves good stir-fries, noodle soups and Thai standards. The forest animals on the menu are rarely available, but even if they are you should avoid them as some, like pangolin, are endangered species and others are poached illegally. Note that the menu has English but no prices.
It's 600m southwest of the market on the road closest to the river, opposite the Sekong Hotel.