Son Doong Cave: the world's largest cave and the 2026 expedition
Hang Sơn Đoòng is the largest cave passage on the planet: 38.5 million cubic meters, about 9 km long, with a ceiling up to 200 m high. There's jungle growing inside, a river running through it and clouds that form under the roof. Only one company takes visitors in, Oxalis Adventure, and the six-day expedition costs $3,000 (80,000,000 VND) per person.
There are 1,000 places a year, and the season runs January to August. As of September 2026, Oxalis says its 2027 and 2028 seasons are already sold out, so booking Son Doong is a plan for several years out. You need to be 18 to 70, and without real outdoor experience your application won't be approved. If you don't want to wait, there are alternatives nearby: Hang En, Hang Va and the Tu Lan cave system.
Son Doong is in Phong Nha-Kẻ Bàng National Park. Since 1 July 2025 that's Quảng Trị province: Quảng Bình was merged into it, and new addresses put the cave in Thượng Trạch commune. Groups meet in Phong Nha town, and the nearest airport is Dong Hoi (VDH), about an hour's drive away.
What Son Doong is and why it's "the largest"
Son Doong is a karst cave, 2–5 million years old, near the Lao border. An underground river carved a passage about 9 km long through the limestone. In two places the roof collapsed, creating dolines, sinkholes that let sunlight in. Under them grows real jungle, with trees over 30 m tall, ferns and vines.
- Son Doong Cave (Hang Sơn Đoòng): The world's largest cave passage — Oxalis only, $3,000, January–August
- Hang En Cave (Hang Én): Day 2 of the expedition — Or a 2-day tour for 9,500,000 VND ($358)
- Ban Doong village (Bản Đoòng): Bru-Van Kieu village on the trail to the entrance, day 2
- Oxalis Adventure office (Oxalis Phong Nha): Briefing and gear fitting on day 1
- Chay Lap Farmstay (Chày Lập Farmstay): Night after you exit the cave, day 5, included
- Dong Hoi Airport (Sân bay Đồng Hới (VDH)): Oxalis picks up here or anywhere in Dong Hoi — About 1 h to Phong Nha
Fact sheet
| Detail | Value |
|---|---|
| Location | Phong Nha-Kẻ Bàng NP, Thượng Trạch commune, Quảng Trị (Quảng Bình before July 2025) |
| Entrance coordinates | 17.4569, 106.2875 |
| Open to visitors | August 2013 |
| Operator | Oxalis Adventure (the only one) |
| Price 2026 | $3,000 / 80,000,000 VND |
| Length | 6 days / 5 nights, 4 of them in the jungle and cave |
| Season | January to August |
| Places per year | 1,000 (100 groups of 10) |
| Age | 18–70 |
| Status | Part of a UNESCO World Heritage Site since 2003 |
How it was found
A local man, Ho Khanh, found the entrance on 10 December 1990. He was searching the forest for agarwood, sheltered from a storm under a cliff and heard a river roaring somewhere in the dark. He had no way to mark the spot and lost it. He only found it again in 2008. In spring 2009 he led British cavers from the British Cave Research Association (BCRA), headed by Howard and Deb Limbert, to the entrance.
The 2009 expedition was stopped by a wall of calcite and only got past it in March 2010. They called it the Great Wall of Vietnam. The survey showed that Son Doong is the world's largest cave passage by volume, with a cross-section about twice that of the previous record holder, Deer Cave in Malaysia.
What's inside
- Two dolines where the roof has fallen in. Under the second is a forest cavers named the Garden of Edam; above the first is a viewpoint called "Watch Out for Dinosaurs".
- An underground river with see-through, eyeless fish and shrimp.
- Clouds under the roof, where warm air from the dolines meets cool cave air.
- Stalagmites up to 80 m tall, the best known being the "Hand of Dog".
- Cave pearls the size of baseballs behind the Great Wall.
- The Great Wall of Vietnam, the calcite wall at the far end that the expedition climbs to get out.
In January 2011 National Geographic ran a major feature on Son Doong with photographs by Carsten Peter, and that's when the rest of the world heard about it. The first paying visitors went down in August 2013. In May 2015 ABC's Good Morning America broadcast live from the expedition camp in Hang En and from inside Son Doong.
Tour price and what's included
The Oxalis Adventure expedition to Son Doong costs $3,000, or 80,000,000 VND, per person in 2026. The price is the same for every date, and there's no one to compare it with: Oxalis is the only company allowed to take visitors into the cave.
What $3,000 covers
| Category | Included |
|---|---|
| Transfers | Pick-up and drop-off anywhere in Dong Hoi, transport to the trailhead and back |
| Nights | Night 1 at Commander Lodge in Phong Nha, nights 2–4 camping (one in the forest, two in the cave), night 5 at Chay Lap Farmstay |
| Food | All breakfasts, lunches and dinners, vegetarian options available |
| Gear | Helmet, headlamp, gloves, harness |
| Team per 10 guests | 1 cave expert, 1 guide, 6 safety assistants, 2 chefs, 18 porters |
| Insurance | Tour insurance, payout capped at 50,000,000 VND (~$1,900) |
| Fees | Park entrance and environmental fees |
What it doesn't cover
- International flights to Vietnam
- The domestic flight to Dong Hoi
- A night after the tour if you don't fly out on day 6
- Your visa and proper travel insurance with trekking and evacuation cover
- Personal kit: boots, clothes, a power bank
💬 "Due to the remote location, the rescue team and medical assistance may take several hours to reach the casualty." — safety notes, oxalisadventure.com, 2026
Total budget
| Item | USD | Notes |
|---|---|---|
| Oxalis expedition | 3,000 | Two hotel nights already included |
| Return flight to Hanoi or Ho Chi Minh City | 600–1,500 | Depends heavily on where you fly from |
| Domestic flight to Dong Hoi and back | 60–100 | Vietnam Airlines, Vietjet |
| Extra night in Phong Nha or Dong Hoi | 15–60 | If your flight isn't on day 6 |
| Food outside the tour | 30–60 | 2–3 days before and after |
| Boots and clothing | 50–150 | If you don't own them already |
| Travel insurance, e-visa if needed | 50–150 | Make sure caving and evacuation are covered |
| Total | 3,805–5,020 | — |
Currency converter
Most people fold Son Doong into a longer Vietnam trip, so the long-haul flight is shared with everything else. For more of the country's wild side, see our guide to Vietnam's national parks.
The route, day by day
The expedition is six days and five nights. Day 1 is the briefing and day 6 is the transfer out; the four days in between are in the jungle and the cave. You hike through Hang En, rope down 80 m into Son Doong, sleep two nights under the dolines and climb out over the Great Wall. Groups are capped at 10.
| Day | Route | Highlights |
|---|---|---|
| Day 1 | Arrive in Phong Nha | Safety briefing, museum visit, gear fitting, dinner with the team. Night at Commander Lodge |
| Day 2 | Trailhead → Ban Doong village → Hang En → camp near the Son Doong entrance | 14 km, around 30 river crossings, 150–350 m of elevation change |
| Day 3 | High passage → 80 m descent → Doline 1 camp | First night inside Son Doong |
| Day 4 | Camp 1 → "Watch Out for Dinosaurs" → Doline 2 camp | Fixed ropes, the Garden of Edam |
| Day 5 | Great Wall → exit → Chay Lap Farmstay | Underground lake crossing, ~18 m ladder and ~72 m of rock on ropes |
| Day 6 | Chay Lap Farmstay → Dong Hoi | Transfer to your train, flight or hotel |
Day 1: briefing in Phong Nha
The group meets in Phong Nha town. The team runs a safety briefing, walks you through the expedition museum and fits helmets, harnesses and lamps. Dinner with the guides, then a night at Commander Lodge in the middle of town.
Day 2: jungle, Ban Doong and Hang En
The longest walking day: 14 km through primary forest. The trail drops to the river and crosses it around 30 times, with 150–350 m of elevation change. On the way you pass Ban Doong (Bản Đoòng), a village of a few Bru-Van Kieu families, then walk through Hang En. Oxalis describes it as the third-largest cave in the world by volume, with a sand beach and a river under the roof. You sleep in a forest camp near the Son Doong entrance.
Day 3: into Son Doong
In the morning you cross a high-level passage about 700 m long, then descend 80 m into the main chamber in a harness, with a safety line. The scale hits you immediately: your lamp lights the floor and the nearest walls, and the ceiling disappears into black. The trail leads to the first doline, where you can see the sky through the hole in the roof. Camp 1 is right there.
Day 4: to the second doline
The route crosses a giant chamber, climbs fixed ropes and passes the "Watch Out for Dinosaurs" viewpoint, named for the view over the jungle below. The second night in the cave is at the camp by Doline 2, in the forest called the Garden of Edam. This is where you're most likely to see clouds under the roof.
Day 5: the Great Wall and out
The last day in the cave is the most technical. First the group crosses an underground lake, then climbs the Great Wall of Vietnam: about 18 m up a ladder and another 72 m or so of steep rock on ropes. Behind the wall is the way out. Then it's a trek to Chay Lap Farmstay, where a shower, a bed and dinner are waiting.
Day 6: heading back
After breakfast at the farmstay, Oxalis drives the group to Dong Hoi: your hotel, the station or the airport. If your flight is late that evening or the next day, book the extra night yourself.
Booking and the annual quota
You book Son Doong years ahead, not months. As of September 2026, Oxalis's tour page says the 2027 and 2028 seasons are fully booked. The FAQ further down the same page is more cautious about 2028 and says a few places are left. Ask about remaining places and the waiting list directly at oxalisadventure.com.
How to book
- Go to oxalisadventure.com → Son Doong Cave Expedition
- Pick an available date or join the waiting list
- Fill in the application: passport, contacts, medical questions and a detailed account of your outdoor experience
- Wait for approval
- Pay the deposit to secure the place (Oxalis gives the amount when it confirms)
- Pay the balance by the date in the contract
They read the application properly. Oxalis says plainly that answers like "I walk a lot" or "I go to the gym" get rejected. What they want is real experience: multi-day treks, climbing outdoors rather than only on a wall, caving.
💬 "Be detailed in your answers, otherwise your reservation will be rejected — 'regular walking', 'going to the gym' are not considered detailed." — oxalisadventure.com, booking information, 2026
Cancellation terms
| When you cancel | What you lose |
|---|---|
| 90 days or more before | 7,000,000 VND (~$265) per person, the rest is refunded |
| 45–89 days before | 50% of the tour price |
| Less than 45 days before | 100% of the tour price |
The quota
Son Doong takes 1,000 visitors a year: 100 expeditions of 10. In 2025 every place was used.
Closed months: September to December. In the rainy season the rivers in the valley and inside the cave rise, the crossings become dangerous, and no tours run.
Who can go
- Aged 18 to 70
- Recent outdoor experience, described in the application
- Medical questionnaire, plus a doctor's note if asked
- A signed liability waiver
The expedition isn't for pregnant women, children or anyone with serious health problems. Oxalis can turn down an application after reviewing it.
Fitness and what to pack
You need to be in good shape. This isn't a walk; it's four days of trekking with river crossings, ropes and ladders. Oxalis rates it "Challenging", the top of its difficulty scale.
The physical side
| Challenge | Numbers | When |
|---|---|---|
| Trekking | Up to 14 km a day, 150–350 m up and down | Day 2 and the exit |
| River crossings | Around 30 in a day | Day 2 |
| Descent | 80 m in a harness on a safety line | Day 3 |
| Great Wall climb | ~18 m ladder + ~72 m rock on ropes | Day 5 |
| Humidity | 80–95% in the cave | Throughout |
Start training 3–6 months out: long hikes with a pack over rough ground, stairs and hills, leg and core work. If you do multi-day hikes regularly, you'll manage. If your last one was five years ago, start with Hang En: it's an honest fitness test on the same trail.
💬 "Participants must have completed at least one overnight trekking and camping tour in a forest or mountainous area within the last 12 months (involving a minimum daily distance of 8 km over complex, rocky terrain and an elevation gain of at least 1,000 m)." — participant requirements, oxalisadventure.com, 2026
What to bring
- Boots that are broken in, with good tread, and that dry quickly
- 2–3 sets of quick-dry clothes: T-shirts, light trousers
- A dry set for camp and a warm layer for the night
- Swimwear or shorts for the crossings
- A power bank of 20,000 mAh or more; there's no power for four days
- A camera in a waterproof case, spare batteries
- Toothbrush, toothpaste, wet wipes, insect repellent
- Your own medicines and a small first aid kit
- Tape or knee supports if you have weak joints
What they provide
Oxalis provides the helmet with a lamp, gloves and harness, and the porters carry the tents, sleeping bags and food for the group. Your own pack is just your personal kit for four days. For the rest of the trip, see our Vietnam packing list.
Getting to Phong Nha
Every expedition starts in Phong Nha town, but Oxalis picks you up anywhere in Dong Hoi, the city with the airport and train station 45–50 km away. From abroad that usually means an international flight to Hanoi or Ho Chi Minh City and a domestic hop to Dong Hoi.
Routes to Dong Hoi and Phong Nha
| From | How | Time | Price |
|---|---|---|---|
| Hanoi → Dong Hoi (VDH) | flight | about 1.5 h | 1.4–2.4M VND (~$53–90) |
| Ho Chi Minh City → Dong Hoi (VDH) | flight | about 1.5 h | 1.5–2.5M VND (~$57–95) |
| Hanoi → Dong Hoi | Reunification Express night train | about 10–11 h | from about 600,000 VND (~$23) |
| Dong Hoi → Phong Nha | Oxalis transfer / taxi | about 1 h | included on the tour; taxi 280,000–470,000 VND (~$11–18) |
| Hue → Phong Nha | bus | 4–5 h | about 150,000 VND (~$6) |
| Da Nang → Phong Nha | bus | 7 h | 200,000–250,000 VND (~$8–10) |
Most nationalities enter Vietnam on an e-visa from evisa.gov.vn; some passports get a visa-free stay. Check the rule for your passport before you book flights.
When to arrive
Day 1 opens with the briefing in Phong Nha and you can't be late, so fly into Dong Hoi with time to spare. Leave slack at the end too: the expedition finishes in Dong Hoi on day 6, and a same-evening flight is a gamble. Spare days are well spent on other Phong Nha caves or on Paradise Cave, whose 1 km boardwalk takes half a day.
Where to stay in Phong Nha
Oxalis pays for the first night of the expedition; any extra nights before or after are on you. Town has dozens of hostels, homestays and farmstays:
Areas and specific places are in our guide to where to stay in Phong Nha. For the town itself, food and getting around, see the Phong Nha-Ke Bang travel guide.
Hue, 4–5 hours by bus · Hue weather by month · Bach Ma National Park
Fast Track — no queue at the border
5–10 minutes instead of an hour in the immigration queue
from$11per passenger
Alternatives to Son Doong
If $3,000 isn't in the budget, the seasons are gone or your fitness isn't there yet, Oxalis runs shorter and cheaper trips in the same park. Some use the same trail, and they still get you a night in a cave.
| Alternative | Price 2026 | Length | Age | Why go |
|---|---|---|---|---|
| Hang Én | 9,500,000 VND ($358) | 2 days / 1 night | 16–70 | Same trail as Son Doong day 2, a night on the beach inside the cave |
| Hang Va | 9,400,000 VND (~$355) | 2 days / 1 night | 16–70 | Stalagmite cones rising out of the water |
| Tu Lan Cave Encounter | 6,700,000 VND ($253) | 2 days / 1 night | 16+ | Underground river swims, camp by a waterfall |
| Tu Lan Experience | 2,200,000 VND (~$84) | 1 day | — | Caves and swimming in a single day |
| Hang Tiên | 6,100,000 VND (~$232) | 1 day | — | A huge entrance, big formations, a natural pool |
| Paradise Cave | 270,000 VND (~$10) | 2–3 hours | any | Dry, lit cave, no expedition needed |
From 15 November 2026, Tu Lan Cave Encounter goes up to 7,900,000 VND (~$298). Prices from Oxalis Adventure, September 2026.
Which one?
Hang Én is the best preview of Son Doong. You follow the same trail through Ban Doong and sleep on a sand beach inside a cave Oxalis calls the third-largest in the world. It costs about an eighth of the price. It isn't easy, though: about 25 km of mountain and river paths over two days.
Hang Va is for the visual payoff: cone-shaped stalagmites rising straight out of clear water. Groups top out at 10.
Tu Lan works for tighter budgets and for groups with mixed fitness, from a single day out to a night by a waterfall.
Paradise Cave is for when you want to see Phong Nha but an expedition is off the table. A kilometer of lit boardwalk, no training, a ticket for about the price of lunch.
Hang Én or Hang Va, plus Paradise Cave and Phong Nha Cave, add up to four or five full days for roughly $450–550 instead of $3,000.
Every cave in the park · Paradise Cave · More adventure in Vietnam
Pros, cons and what people say
People who've done Son Doong often call it the best trip of their lives. But it comes at a cost beyond the money: a wait of years, a real screening process and physical work you have to train for.
On TripAdvisor, two things come up again and again: the scale is bigger than any photo, and you should train for it even if you think you're fit.
FAQ — Son Doong Cave
The Oxalis Adventure expedition costs $3,000, or 80,000,000 VND, per person. There are no discounts and no other operators. The price covers transfers from Dong Hoi, two hotel nights, three nights of camping, all meals, gear, a 28-person crew, tour insurance and park fees. International and domestic flights are extra, and so is your own travel insurance with caving and evacuation cover
No. Oxalis Adventure is the only company allowed to take visitors into Son Doong, and independent entry is banned. It's close to impossible anyway: reaching the cave takes a full day of jungle and river crossings, and you get in by roping down 80 m. Anyone offering an "unofficial" way in is breaking the law. The closest experience is Hang En with the same operator for 9,500,000 VND ($358)
Expeditions run January to August; there are none September to December because of flooding. February to April is cooler and drier, with lower rivers. May to August is hot in the jungle, with some heavy showers, though the weather barely changes inside the cave. In practice you pick from what's left: as of September 2026, the 2027 and 2028 seasons are already sold out
Month-by-month weather across the country is in our Vietnam weather guide
The limit is 1,000 visitors a year: 100 expeditions of 10. In 2025 all of them were used. Each group has a 28-person crew: a cave expert, a guide, six safety assistants, two cooks and 18 porters. That's how the park caps pressure on the cave and how Oxalis keeps its safety standard
You need real outdoor experience, and Oxalis checks it in the application: "I go to the gym" gets you rejected. Day 2 is 14 km of jungle with around 30 river crossings, day 3 is an 80 m descent, and day 5 is the climb up the Great Wall, about 18 m of ladder and 72 m of rock on ropes. Train for 3–6 months with long hikes carrying a pack
Hang En is the neighbouring cave the Son Doong expedition walks through on day 2. The Hang En tour is 2 days, 9,500,000 VND ($358), for ages 16 and up. Son Doong is 6 days, $3,000, 18+, with two nights in the cave, the dolines, jungle under the roof and the Great Wall. Hang En is a good fitness check and a great option while you wait for your season
You have three options
- Join the waiting list, because people do cancel and places open up
- Book the next open season, even if it's two or three years away
- Go on Hang En, Hang Va or Tu Lan with the same company and get a night in a cave and the park's jungle now
Read next: Phong Nha caves · Phong Nha-Ke Bang travel guide · Vietnam's national parks · Adventure activities in Vietnam
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