Tu Lan Cave System

The short version

Tu Lan is not one cave, it's a whole system of around ten river caves scattered through jungle and karst near Tan Hoa village, about 70km northwest of Phong Nha town. The trip is built around swimming: you wade and swim into the caves in a life jacket and headlamp, climb out into a hidden valley, and do it again. The otherworldly jungle shots in Kong: Skull Island were filmed right here in 2016. Oxalis is the only licensed operator, and in 2026 the system runs as a 1 to 5 day ladder, from around $78 (2,000,000 VND) for the day version, up to a 5-day expedition around $680 (18,000,000 VND). The trip most people book is the 3-day, 2-night Tu Lan Cave Encounter at around $292 (7,700,000 VND) (Prices checked June 2026).

If you came to be active and you cannot get Son Doong or Hang En, this is the one I'd push you toward. It's the most water-heavy of the big trips and the most fun if you like getting wet.

What the Tu Lan trip is actually like

Oxalis picks you up in Phong Nha around 7:00 to 7:30am and drives the 70km out to Tan Hoa, where you kit up at their office: helmet, headlamp, life jacket, gloves, and trekking boots if you need them. Then you walk into the karst forest. The first cave comes within an hour or so, and the pattern repeats all day: trek through jungle and over rice paddies, swim through a dark flooded passage, pop out into a sealed valley nobody can reach by road, eat lunch on a rock, keep going.

The swimming is the part people remember. Hang Ken is the headline, the longest and prettiest river cave in the system, and you swim a long stretch of it with your headlamp throwing light across the water and walls. The water is cold and clear, the chambers are big and echoey, and basic swimming skills are all you need because everyone wears a life jacket the whole time. The trekking itself is moderate, not punishing, with some scrambling and a short ladder or two rather than ropework.

On the overnight trips you camp at riverside sites. The tents have a thick mattress, a pillow and a sleeping bag, the local chefs cook a proper multi-course dinner over a fire, and you can swim in the river right at camp while an Oxalis staffer keeps watch.

How fit do you need to be?

Moderate. You need to be a confident enough swimmer to cross a flooded cave passage in a life jacket, and fit enough for a full day on your feet over uneven jungle ground with some climbing and scrambling. There's no abseiling on the shorter trips and nothing technical. Oxalis takes people from 16 up, and plenty of normal, reasonably active travelers in their fifties and sixties do the overnight trips fine.

The honest catch is the water. If cold water makes you miserable, or you panic swimming somewhere dark and enclosed, this trip will be a long day. The chambers are wide and the guides are right there, but it is genuinely swimming into a black cave, not paddling at the edge. The 4 and 5-day expeditions are a real step up, with more caves, bigger elevation gain and longer days, so treat those as a fitness commitment rather than a holiday.

Which Tu Lan length to pick

Oxalis rebuilt the Tu Lan ladder in 2026, so the old day-counts you'll see floating around the internet are wrong. Here is the current shape. The 1-day Tu Lan Experience, around $78 (2,000,000 VND), is a brilliant day out and the right call if you cannot spare a night. You get the jungle trek and a couple of cave swims, and you're back in Phong Nha by evening. It's the cheapest way into a serious Oxalis cave experience anywhere in the park.

The cheapest overnight is the 2-day, 1-night Hang Tien-Tu Lan Discovery at around $217 (5,800,000 VND), which pairs a Tu Lan cave with the big dry Fairy Cave and one night of riverside camping. The trip most people should book is the 3-day, 2-night Tu Lan Cave Encounter at around $292 (7,700,000 VND). That is the flagship now, and note it is 3 days, not the 2-day it used to be. You get more caves, two nights out past Tan Hoa, and the swim through Hang Ken. For the small jump over the Discovery, it's what turns a good outing into the trip you talk about afterwards.

Above that, the 4-day, 3-night Wild Tu Lan Cave Explorer runs around $396 (10,500,000 VND), and the longest, the 5-day, 4-night Tu Lan Cave Expedition, is around $680 (18,000,000 VND). Both push deep into the wider system for people who want days off the grid and the bigger, wilder caves the short trips never reach. Only book a 4 or 5-day if the idea of being soaked and remote for that long sounds like the point rather than the price (Prices checked June 2026).

Kong: Skull Island and the village that floods every year

The Kong connection is real, not marketing. Principal photography ran from October 2015 to March 2016, and the crew built sets around Tan Hoa and used the Tu Lan caves, with Rat Cave (Hang Chuot) standing in for the film's cave scenes. Oxalis handled the local logistics, hiring villagers and renting cornfields so the valley looked untouched on screen.

Tan Hoa itself is worth understanding, because it's not a normal Vietnamese village. It sits in a basin that floods catastrophically most years in October and November, water rising as high as 12 metres in a bad season. After a brutal flood in 2010 the community built around 700 floating houses, simple structures on oil-drum pontoons that ride up the rising water and settle back down when it drains, so families and their belongings stay dry. The cave tourism was designed around the same problem, which is why the season tracks the floods so closely. In 2023 the UN's tourism body named Tan Hoa one of its Best Tourism Villages, the only winner in Vietnam that year.

Tu Lan or Hang En?

Both are Oxalis and both are excellent, so this comes down to what you want from a day underground. Hang En is the iconic giant cave: you camp on a beach inside one of the largest cave mouths on earth and watch thousands of swifts pour out at sunrise. It's the photo most people carry home, and it runs as a 2-day, 1-night trip at around $333. On price, that sits just above the Tu Lan Discovery and just below the 3-day Encounter, so the cost is not really the deciding factor here.

Tu Lan is the active one. Instead of a single huge chamber, you move between many smaller caves, and the swimming is the whole experience rather than a side note. You'll see more variety of landscape, swim far more, and feel like you earned it. So: Hang En if you want the one unforgettable image and don't mind that the swimming is minimal. Tu Lan if you want to be in the water all day, cover multiple caves, and pick the trip that asks more of you.

What to bring and the leech situation

Wear quick-dry long trousers and a long-sleeve top, and on the overnight trips bring a second set, because you'll be soaked by lunch every day and nothing dries out there. The single best thing you can pack is a pair of thick, calf-length, tightly woven socks. They're your blister protection and your leech barrier in one. Leeches turn up on the wet jungle sections and they're more annoying than dangerous, small things that latch on and let go, so a quick check now and then handles it.

Oxalis provides the kit that matters: helmet, headlamp, life jacket, gloves, trekking boots, plus tents, sleeping bags and mattresses on the overnighters. Still bring your own dry bag for your phone, sunscreen, a hat and any medication you need. Tip the porters and guides at the end if they looked after you, which they almost always do.

When to go and how to book

The season runs December to August. The caves close through the autumn flood months, roughly September to November, because the same rivers you swim through turn dangerous when the water rises. Inside the season, the drier early months give you the most comfortable trekking, while the warmer months make the cold cave water feel like a relief rather than a shock. Any month it's open is a real trip.

Book directly with Oxalis on their official site. They hold the only license to run the Tu Lan system, so anyone else selling it is reselling Oxalis with a markup or running you around. Going direct means you can ask straight questions about water levels, fitness and dates before you commit. Spots are far easier to get than Son Doong, but the 3-day Encounter fills up in peak months, so once your Phong Nha dates are fixed, lock it in a few weeks ahead rather than hoping for a walk-up.