Check out Cave Alley, the first 20 km of Route 12 with a half-dozen caves. Take a boat ride through the world famous 7.5-km Konglor Cave in the Limestone Forest. Travel to the Hinterlands in the mountainous east, which is loaded with caves including the 9.5-km-long Tham Xebangfai river cave.

Cave Alley

Cave Alley, the first 20 km of Route 12 as it leaves Thakaek, wanders through a natural amusement park with a half dozen caves. Some house ancient Buddha images. Others have underground rivers with swimming and fishing spots. Cave Alley also launches “The Loop” that explores the Nakai Plateau and Limestone Forest with Konglor Cave.

Tham Xang: Climb to Elephant Mountain’s shaped like a mahout in action, just 5 km from Thakaek off Route 12. An easy hike wades across a shallow river and through vegetable gardens, before a staircase, peering towards the Mekong, lumbers up the mountainside to Tham Xang (Elephant Cave).

Over the years, the cave hid a box containing Buddhist literature, provided bat droppings for making gunpowder during World War II, and afforded refuge during the Indochina War. Locals once considered Tham Xang as cursed because of a “monster” rock formation inside. In 1956, they dynamited the evil image, which opened a chamber with an elephant head figure, which is now a Buddhist shrine. To reach this religious site, follow the passage that veers right behind the large golden Buddha.

Next to the cave, a trail leads up Elephant Mountain. Bamboo handrails and wooden steps, constructed by villagers, assist in a moderate trek to a viewpoint. From here, visitors can look over rice paddies, villages, streams, and surrounding mountains. A further 40-minute rigorous climb reaches the peak with views to the Mekong River and Thailand’s That Phanom.

Tham Xang and Elephant Mountain is the first stop on Cave Alley, just 9 km from Thakaek on Route 12. At Km 7, keep right. The cave entrance is directly ahead.

Tham Xieng Liab: Venture into Tham Xieng Liab, where the sun peeks through holes in the cave’s roof, providing natural light on your 200-metre expedition through a mountain. Hidden behind a rock landslide under a 300-metre-high cliff, Xieng Liab Cave’s entrance launches a 400-metre hike or boat ride up the Houei Xieng Liab Creek. You can continue into the oversized opening by boat during the Green Season (May-October) or by foot in the dry season (November-April), though the walk over jagged boulders requires careful balance and your feet will get wet. 

Locals named the cave after a former novice monk (Xieng), who was “sneaking around” (Liab) in the cavern to catch a glimpse of a mountain hermit’s daughter, with whom he was in love. Legend aside, you’ll wander past bizarre limestone formations dangling from the ceiling, and some locals say you may stumble into prehistoric wall paintings. Paa faa (soft-shelled turtles) and bats inhabit the cave, while the rare Francois langur and recently discovered kha nyou (Laotian rock rat) have found a habitat in cliffs around the cave. The stream and trail exit to a pleasant swimming hole and view of the valley beyond.

To reach Tham Xieng Liab, continue along Cave Alley on Route 12 to Km 12 and Ban Songkhone Village. Cross the bridge over the Houei Xieng Liab Creek and stop at the parking area with kiosks selling refreshments. From here, take a boat up the creek or walk along a 400-metre trail to the cave.

Tham Pha Chan & Khoun Nam Don: Tucked in a distant corner of Cave Alley, Tham Pha Chan (Sandalwood Buddha Cave) cuts through a limestone mountain, with a stream carving the 600-metre tunnel. An enormous entrance delivers you to a domed rock cathedral. On a ledge 15 metres above the cave’s floor, a small monastery displays several Buddha images. The most prominent and revered statue, a sandalwood (mai chanh) Buddha, stands among them. Further on, long-eared bats roost in the upper crannies, and are better left undisturbed, though photos generally don’t fluster them.

Monks once inhabited the cave, but villagers now use it for meditation and religious celebrations. During the Lao New Year in mid-April, hundreds of locals flock to the cave to sprinkle the stream’s waters on the sacred sandalwood Buddha’s head. They also use the party-like atmosphere to dive into the underground creek and splash around. 

A short walk from Tham Pha Chan along the Nam Don River ends at Khoun Nam Don, the main source of the cave’s brook that flows to the Mekong. The rivulet emerges from a cave and empties into a lagoon below a 300-metre-high cliff. Boat captains at the dark crevice offer rides into the void, when the rainy season waters backflow into the cave. The cavern breaks off into an unmapped labyrinth that penetrates 3 km into the mountain. In the 1990s, a French survey team ventured 150 metres into Khoun Nam Don and discovered a new genus of blind cave fish at a depth of 23 metres.

The best time to visit Tham Pha Chan and Khoun Nam Don is from November-May, when the waters recede. During the Green Season (June-October), the cave’s stream can rise 3 metres, making it impassable by foot. To reach this natural wonder, travel a few km past Xieng Liab Cave, where a turnoff takes you on a rough road for about 90 minutes. You can book a tour at Thakaek’s Visitor Information Centre or through a local tour operator.

Buddha Cave Park: Enter the dark hollow discovered in 2004 by local villager, Mr Boun Nong, who hit a mother lode of ancient Buddha images inside. Word of his find went worldwide, and locals have transformed Tham Pa Fa (Buddha Cave) and its surrounding area into a nature park.

A rickety walkway once zigzagged over a lagoon to a 20-metre bamboo ladder climbing a cliff to the vine-covered cave. Now, a concrete staircase scales the crag concealing 229 Buddha statues, ranging in height from 15 cm to over 1 metre.

Some historians date Mr Boun’s discovery to the Sikhottabong Era (6th century), while others point earlier to Khmer and Vietnamese origin. In other words, no one knows, and palm leaf manuscripts in ancient Lao, Khmer, Lanna, and Pali scripts found in the cave further muddies the waters.

Today, vendors sell herbal cures, refreshments, and local handicrafts at Tham Pa Fa Market at the Buddha Cave Park entrance. From here, a bridge delivers tourists to the stairs to the main attraction. A boat also awaits to paddle you into the lower cave, which may have hid the Buddhas before flooding forced an upward move.

From the Tham Pa Fa Market, follow a 400-metre shady trail to Nong Tao (Turtle) Lake and the Tham Pla Xaem Cave. Limestone karsts and lush vegetation circle the lake’s calm waters, perfect for a swim or peaceful picnic. You can try net fishing by hiring a boat and captain at the dock. From the small jetty, a short rocky trail clambers to Tham Pla Xaem (Blind Fish Cave). From August to November you can kayak into the resurgence river, which catches Nang Tao and Nam Don’s rainy season overflow.

To reach Buddha Cave Park from Thakaek, travel on Route 12 to Km 7. Turn left at the sign for the cave, go straight for about 500 metres, stay right along the old French railway bed, cross the Nam Don River, and continue for some 4 km along a dirt road until you reach Na Khang Xang and the parking area. Photography in Tham Pa Fa is prohibited.

Tham Nang Aen: For family fun or a soft underground adventure in a user-friendly cave network, stop at Tham Nang Aen (Sitting and Flirting Cave) for an amusement park-like  experience. An inviting set of stairs slowly rises to the subterranean abyss. After stepping through the eerily wide, narrow slit peering into the darkness, the cavern opens into a well-lit natural wonderland.

Cement walkways seamlessly follow the inner-cave’s contour, blending with the backdrop as it criss-crosses between limestone ledges, rising and falling with the 30-metre-high grotto. Soft fluorescent light guides these footbridges to rocky windows opening to the forest. Below, boats await to take passengers 1 km across an underground lake and up the Nam Don River’s hidden tributary, but a tightening passageway ends the ride. 

The cave’s legend relates to that of Tham Xieng Liab. According to lore, Xieng, the young former novice who went looking for the beautiful daughter of the hermit at Tham Xieng Liab Cave, met with her at the entrance of Tham Nang Aen. Here the two lovers sat (nang) and flirted (aen kan). Hence the cave’s name.

Tham Nang Aen is located 18 km east of Thakaek on Route 12. A sign points to the short road to the cave. Vendors operate food stalls and sell fresh food at the entrance from November-April.

Tham Pa Nya In: To enter this little-known cave named after an archangel featured in many Lao stories, climb cement stairs, and then creep through a small passageway. On the left, you’ll see two Buddhist shrines and several Buddha images. Then, carefully ease your way down to a 75-metre-long underground lake. A leg of the cave runs deeper into the mountain on the other side of the lake. Swimming or washing in the lake is prohibited, as the water is considered holy, and don’t forget to bring a torch.

To reach the cave from Thakaek, travel 17 km east on Route 12, and turn left through a blue cement gateway (there is no sign) and continue 400 metres to the cave.

The Limestone Forest

Konglor Cave: Board a long-tail boat at Konglor Village and take peaceful journey down the karst-lined Nam Hinboun River. You’ll pass riverside vegetable gardens, and then pause at a jumble of boulders at the foot of a mountain. Here, the river enters a black void that opens into a stadium-like cavern with a ceiling topping 100 metres. The 30-metre-wide waterway then flows 7.5 km by sandy beaches and rock formations named for their shapes: “Buddha”, “frog”, “owl”, “soft-shell turtle”, and “fish trap”.

Locals didn’t always fully navigate Konglor. Prior to the 1600s, no one knew the Hinboun flowed through mountain. According to local lore, five villagers set off one morning about 400 years ago in a dugout to see if there was light at the end of the abyss. They spread rice husks along the way to help them find the way back, but by midday, they reached the other side. The shortcut then experienced plenty of canoe traffic for the 2.5-hour paddle until motorized long-tails cut the journey through the Phou Hin Poun National Protected Area cave to about an hour.

To reach Konglor from its gateway, Ban Na Hin on Route 8, travel 40 km south on the newly completed road. A slightly longer, but more adventurous boat trip up the Hinboun River, begins in Naphouak Village on Route 13. A choice of accommodation and restaurants are available in the Konglor and Ban Natan area.

Tham Heup: Tham Heup Cave’s massive black-hole entrance in the Limestone Forest lures the curious. The 20×15-metre opening bores more than 1 km through the mountain, and is easy to navigate. You’ll pass rock formations, a pond, and a beach, while venturing into the spacious cavern. Upon exiting, you can walk 3-4 km through a sacred forest to the remnants of an abandoned temple swarmed in jungle growth and Tham Jong, a small Buddha cave.

Many hiking the 1.5-km Ban Nahin Trail to Tad Nam Sanam and Tad Mouang Waterfalls extend their hike to Tham Heup. The path to the cave starts at Ban Nakhok Village, where you cross the Hinboun River and take a 1.5-km walk to the entrance. Those visiting during the rainy Green Season (May-October) can boat to the cave on a Nam Hinboun feeder stream. You need a local guide to visit Tham Heup, which can be arranged in Ban Nakhok.         

Khammouane’s Hinterland

Venture to the legendary Ho Chi Minh Trail in the eastern mountains and explore caves accessed from Langkhang Town. Boat along Xebangfai Cave’s underground river. Climb inside sacred Tham Phi Seua Cave. Inspect Tham Phabang’s 300-year-old wooden Buddha. Most caves in Khamouanne’s Hinterlands are quite easy to reach, with an official guide service and tour operators in Thakaek ready to help.

Xebangfai Cave: Retrace part of a 2008 National Geographic expedition into the little-known Xebangfai Cave (Tham Namlot). Climb aboard a long, narrow wooden boat on the Xe Bang Fai River, and enter the vast darkness of a 7-km giant tunnel. You’ll navigate the river for about 2 km, as it cuts beneath the limestone karst mountains of the Hin Nam No National Protected Area. Rapids interrupt the boat ride, so it’s time for a walk to inspect the chamber measuring an average of 76 metres wide with a 56-metre ceiling.      

Natural decorations, such as majestic flowstones and twinkling crystal forms, adorn the cavity. A climb up one branch opens to another chamber that locals call the “Dragon Hatchery”. Continue to the Dragon’s Balcony and roof opening that offers dim lighting. Xebangfai Cave emerges at Ban Nong Ping and the village’s 200-metre-wide fishing pond.

Nong Ping villagers traditionally thought the Xe Bang Fai originated in the cave. They named it “Tham Khoun”, which literally translates to “the cave at the source of the river”. Villagers showed the unknown cave to a French exploration team in 1905, who found this was one of the largest river caves in the world. A second French team investigated the anonymous tunnel in 1995, before the National Geographic expedition placed it on the global stage.

Visitors to the cave need a local guide from the Village Guide Service. You can arrange guides at Ban Nong Ping and other villages in the area, though they have limited English. Tour agents in Thakaek also use local guides, as their knowledge is essential.

Nong Ping is 14 km from Boulapa Town, which is a 30-km drive south and then east of Langkhang (Nongchan) Town on Route 12 from Thakaek. You can also reach the cave by boat from Ban Phakphanang on the Langkhang-Boulapa road. Nong Ping offers homestays, a 4-room lodge with fans, and local meals.

The Village Boating Group offers two itineraries. The “Short Trip” paddles 300 metres into the cave, before disembarking for a fairly steep climb to the Dragon’s Balcony. The “Long Trip” runs the full 2 km to the cave’s rapids, and you return via the Dragon’s Balcony.

Tham Bing: Try this alternative to entering Xebangfai Cave. Head to the high cliff north of the cave’s mouth. Find the small opening and creep inside to a 700-metre passage lined with flowstone and columns. This leads to a high cliff inside Xebangfai. The 1-hour, moderately difficult excursion starts and ends at the river cave’s resurgence pool.

Tham Long: Take a 30-minute walk on a 300-metre path from Ban Nong Ping to Tham Long (Coffin Cave). The cave’s rock-ledge entrance opens to a pair of caverns. The first once held hardwood coffins from a pre-war era. The second cavity sheltered thousands of villagers and North Vietnamese soldiers travelling on the Ho Chi Minh trail during the Indochina War.

Tham Phabang: Visit this narrow cave and view its 300-year-old wooden Buddha. The thin, 1-metre-tall standing Buddha has withstood aging, natural rotting, monkey attacks, getting knocked over, and termites, though it did suffer a break over the centuries. You can view the heavy bronze Buddha (Phabang), for which locals named the cave, at the Ban Nakheu Temple. The Phabang originally carried the title of Pha Thong (Bronze Buddha). However, villagers renamed it Pha Ong Saen (Buddha 100,000) after thieves tried to steal it, but the Buddha magically gained weight, which thwarted the theft.

You can reach the cave by hiring a local guide from the Ban Nakheu Village Guide Association, who will take you 1.5 km across paddy fields and up a stream to the cave.

Tham Pi Seua: Join the growing number of tourists making their way to the sacred Tham Phi Seua (Tiger Spirit Cave). Start at Ban Phon Ton with a village guide, and walk 2.5 km through rice paddies and forest. A 15-metre climb leads to the cave’s arched entrance spanning 40 metres wide and rising 25 metres. From here, step onto a rocky, slanting trail, with pools on the right. Continue along the trail to a junction. Go left past some large boulders to reach a majestic and sacred 40 x 40-metre chamber, believed to be inhabited by spirits. Wildlife around this cave includes Francois langurs and macaque monkeys.

Tham Nam Ork: The Houay Hok Stream (Tham Nok Aen) passes through three caves near Ban Thongxam. Start at Tham Nam Ork, a massive resurgence chamber with an odd boulder ceiling. The cave self-cleans due to the seasonal change in water flow. To reach the Tham Nam Ork, hike 6 km upstream from the village

Tham Nok Aen: Wade through the 60-metre river tunnel that passes under a limestone cliff. A beach lines the Houay Hok on this underground journey, though it flows at a constant depth of 1.5 metres for those who’d rather float. You can also explore passages worming into the left bank’s wall. Swallows (Nok Aen) nest in the cave, as do bats, and during the Indochina War, some 3,000 North Vietnamese troupes hid there, as seen in their leftover cans and personal items. 

Tham Pak Tham: The third Houay Hok tunnel is 2.7km upstream from Ban Thongxam. The cave’s deep resurgence makes it perfect for a swim.