Ask fellow travellers why they came to Khammouane, and more than 90% will say, “Caves,” as caverns pock the limestone mountains in and around Phou Hin Poun National Protected Area (NPA). Khammouane’s “Water World” walks hand in hand with the caves, some of which spring rivers. Take a local longboat into a cave or along the many rivers to waterfalls and lagoons. In Thakaek, you can explore ancient sites and provincial buildings frozen in time.
In the Limestone Forest, Konglor Cave remains the most popular as you can boat through the 7.5-km tunnel with rock formations and sandy beaches to Ban Natan.
While there, trek to Tham Heup Cave, a massive black hole that bores more than 1 km into the mountain. You’ll pass rock formations, a pond, and a river beach, while venturing into the spacious cavern.
Closer to Thakaek, explore “Cave Alley” and its row of grottoes. Climb a short set of stairs to Tham Xang (Elephant Cave) that once hid Buddhist literature, provided bat droppings for making gunpowder, and afforded refuge during the Indochina War.
You can enter Xieng Liab Cave by boat during the Green Season, or by foot when the waters are low. The sun peeks through holes on the 200-meter expedition.
Follow a stream into Tham Pha Chan (Sandalwood Buddha Cave), which cuts hundreds of meters through a limestone mountain to a domed rock cathedral displaying Buddha images, the most scared being a 1-metre-tall sandalwood image.
Be sure to visit Buddha Cave Park and Tham Pa Fa (Buddha Cave) discovered in 2004. A short concrete staircase leads to the vine-covered cavern concealing 229 Buddha statues.
Then take a 400-metre trail to Tham Pla Xaem (Blind Fish Cave). From August to November you can kayak into the narrow cave which flows inwards during the rains.
Stop at Tham Nang Aen (Sitting and Flirting Cave) and step through its narrow slit The cavern’s cement walkways follow the inner-cave’s contour, and lights guide the way to rocky windows opening to the forest. Boats await to take passengers on a 1-km voyage into the cave.
Climb up cement stairs, and creep through a small passageway to little-known Tham Pha Nya In Cave and its Buddha images. Then, carefully ease your way down to a 75-metre-long underground lake.
In The Hinterlands, climb to Tham Phi Seua (Tiger Cave), and step onto a rocky, slanting trail with pools on the right. Continue to reach a massive chamber.
Tham Phabang Cave holds a 1-metre-tall standing wooden Buddha that could be 300 years old. A larger, heavy bronze Buddha, Pha Ong Saen, which used to reside in the cave, has been relocated to a nearby village temple.
One of Khammouane’s most spectacular underground tunnels, Xebangfai Cave, allows the Xe Bang Fai River to pass through 9.5 km of rock.
Khammouane’s Limestone Forest doesn’t disappoint waterfall buffs. You can investigate Tad Mouang’s 18-tier cascade near Ban Na Hin, while Tad Nam Sanam plunges off a Phou Phaman Mountain cliff a half km away.
From Ban Na Hin, trekkers can follow a Hinboun River tributary trail to a rest stop overlooking Tad Nam Sanam Waterfall, a twin cataract cascading off Phou Phaman Mountain and over five rocky steps.
Enter paradise at Khoun Kong Leng Lake (Blue Lagoon), with large fish swimming in its emerald waters. Trails circle the limestone-filtered lake with its forested grounds. Swimming is permitted near the wooden footbridge.
Near the lake, the Hinboun River tumbles over the Ban Khon Keo Rapids, a series of rocks near Khon Keo Village. The river then flows to calmer pools, ideal for swimming or fishing with the locals.
You can also cross the Nam Kong Leng River on a bamboo bridge to an upstream path to the main pool, great for a dip.
In “Cave Alley” a boat awaits underneath Buddha Cave at a lagoon leading into a crevice.
Nearby, Nong Tao Lake presents a postcard for swimming or paddling to fish, and Pla Xerm Cave at the far end offers kayak trips.
Across Route 12, you can explore Nang Aen Cave’s underground labyrinth in a rowboat.
Near town, take a swim at isolated Tha Falang on the Nam Don River.
In the Nakai Plateau, stop at the Nam Theun 2 Dam (NT2), where you can watch the river gush through the concrete wall and into a cobblestone canal. At the NT2 Visitor Centre, learn how the dam operates, who benefits, and how it lessens negative environmental and social impacts.
Upriver, NT2 has created a Reservoir Retreat, where the wetlands are already flourishing. A guesthouse at Thalong offers activities including boating and fishing.
Thakaek is rising from its 100-year-long dormancy as “Guest Landing”, named for its past role as a pier and respite for traders and travellers. Today, Old Thakaek has transformed its French colonial structures into guesthouses, restaurants, and noodle shops huddled around the Night Market.
The Sikhottabong Empire originally built Thakaek’s iconic 29-meter-high, golden-tipped That Sikhottabong Stupa in the 6th century. Lane Xang Kingdom’s King Phothisarat and King Saysethathirath refurbished it in the 1500s to its present form.
A sizeable statue of 8th century King Sikhot, who ruled over the central Laos expanse, greets visitors to the stupa.
Visit the Cultural Village just outside the religious compound. Nine different ethnic groups present a living museum with traditional houses, from which they display their lifestyles, and produce and sell their handicrafts.
Try figuring out how the Sikhottabong Kingdom’s 9th century workers constructed the Kampaeng Yak (Giant Wall). North of Thakaek, you’ll find a 75-metre-long uninterrupted section of the sandstone stack. Many of the carefully carved blocks run 5×1 metres in size, and are precisely assembled up to 16 metres highs.
Further into the forest, the fortification climaxes at a 10-metre-tall bastion with an entrance portal. French colonials converted this end of the wall into a Catholic Church with a shrine to the Virgin Mary. Today, several rows of benches face the altar merged into Kampaeng Yak.