Son Doong Cave

Son Doong Cave

The world's biggest known cave

More on Phong Nha

There’s a place underground so large, it can fit an entire New York City block, complete with 40-storey skyscrapers. Jungles thrive deep inside, as well as towering 80-metre tall stalagmites. When news spread in 2010 about Hang Son Doong it sounded like a children’s adventure tale, too wild to be true. But it does exist. It is now the world’s largest cave and a select number of travellers each year can explore its fantastical inner reaches.

Travelfish says:
Lost world, where art thou?

Lost world, where art thou?

The world is shrinking. In this day and age as a global village, where our network stretches to the deepest pockets of earth and very highest peaks, where information moves instantaneously and it seems people do as well – dinner in Los Angeles, breakfast in Bangkok – it gets to feel like the there is nothing left in this world untouched, undiscovered and unexplored. So imagine what it must have been like for Howard and Deborah Limbert from the British Cave Association to hear local villager Ho Khanh speak of a cave he had once seen with clouds pouring out of its entrance and with the sound of a great river inside.

Born into poverty and with a family to support, Ho Khanh would roam deep into the jungle to source agarwood to trade. On one such hunting trip in 1990, he sought shelter from a storm and came across an opening in a limestone cliff with a river flowing out of it. Though he did not venture in far, he knew that the wind coming from within that it must be a large cave. He left and failed to find it again a few days later, so it slowly faded from his mind until that fateful day with the Limberts.

Howard and Deb Limbert.

Howard and Deb Limbert.

Howard and Deborah Limbert had first visited Phong Nha in 1990 as part of a British Vietnamese caving expedition – they were following a tip from geology colleagues in Hanoi who had highlighted the massive potential of Quang Binh province for long river caves. Phong Nha Cave was being explored in 1990 and 1992, before being opened to tourists in 1995.

After a failed trip to rediscover the entrance with the team in 2007, Khanh went into the jungle using his own money and time to track it down alone. Magic struck in 2008. He sent word to the team and eagerly awaited their return in 2009.

Cave coral formations in Hang En Cave, located just 3 kilometres from Son Doong.

Cave coral formations in Hang En Cave, located three kilometres from Son Doong.

In the first expedition, Khanh and the team were only able to explore less than three miles of the cave, as they were prevented from going deeper by a 60-metre calcite wall they nicknamed the Great Wall of Vietnam. They could see a light-filled space above the cliff, but had no idea what lay behind it until they returned a year later. What they fully discovered in 2010 was the largest cave in the world.

How large? According to Oxalis Adventure Tours, the only official company allowed to operate commercial expeditions into the cave: “At over 5km long, with sections reaching up to 200m tall and 150m wide, Hang Son Doong is large enough to house an entire New York City block, complete with 40 story skyscrapers. With a total measured volume of 38.5 million cubic metres, this comfortably surpasses Deer Cave in Malaysia, which was considered to be the previous record holder. Stalagmites up to 80m high have also been surveyed, the tallest every encountered.”

A 747 could fly through its largest cavern.

If our global village is shrinking, then our underworld universe is expanding. Located within UNESCO Natural World Heritage designated Phong Nha-Ke Bang National Park, Hang Son Doong means “mountain river cave.” Its many awe-inspiring subterranean features have memorable names, from “The Garden of Edam” and “Watch Out For Dinosaurs”, to a 70-metre stalagmite cheekily called “Hand of Dog” (not God). The cave contains unusually large cave pearls the size of baseballs, as well as collapsed ceilings known as dolines that have created jaw-dropping openings allowing daylight to feed vegetation and jungles within. The cave even has its own weather system. More is being discovered every year.

Langur sighting, Phong Nha-Ke Bang National Park.

Langur sighting, Phong Nha-Ke Bang National Park.

The provincial government currently limits Son Doong to 500 visitors a year. The cost of the five-day, four-night Oxalis expedition is US$3,000. Before you balk at the price tag, remember that each group is lead by a professional team of 25+ expert cave guides, porters and a medic. The journey includes descents and climbs with ropes and harnesses and quality equipment – the expedition is not a figurative walk in the park. As well, all supplies must be brought in and out, a full day’s journey by foot through the jungle.

Porters: the heroes of treks across the globe.

Porters: the heroes of treks across the globe.

Even if you can afford US$3,000, tours are sold out at least a year in advance. They are sold out for 2016, with no word yet on whether Oxalis can secure the right from the government for 2017. The limit on the number of operators and tourists minimises the environmental impact while ensuring a high level of safety. We hope this system remains and that attempts by mega-resort developer Sun Group to build a US$212 million dollar cable car to carry 1,000 tourists an hour will be blocked. If the plan for mass tourism goes through, the affect would be devastating. The outlook is bleak: Tourism authorities are pushing for it despite objections from UNESCO and the rest of the sane world.

Walk amongst giants.

Walk among giants in Phong Nha-Ke Bang National Park.

If Son Doong isn’t in your budget, or you suspect you’ll grow too old and brittle waiting – or more likely, that a cable car will be under construction before being able to snag a spot – Hang En Cave, the world’s third largest cave, is a more accessible alternative and will give you a taste of the Son Doong expedition as they both share the same route in/out. In fact, the Son Doong trip spends the first and last night camping in Hang En.

Camping in Hang En: NOT a poor man's Son Doong.

Who said camping was boring?

As of 2016, Oxalis is also the only operator allowed to run trips inside Hang En, applying the same sensitivity to running high quality trips with minimal environmental impact, though more people and trips are allowed for Hang En. At 6,500,000 dong (or US$295) we felt it was a trip of a lifetime and worth the price. See our Hang En Cave coverage for more details.

And if you know that you’ll just never be able to experience Hang Son Doong, thankfully in this modern day and age, in our shrinking global village, you can immerse yourself virtually in National Geographic’s stunning high-resolution 360 interactive.

Oxalis Adventure Tours: Phong Nha Commune, Son Trach Village, Bo Trach; T: (052) 367 7678 F: (052) 367 7679;;
Ho Khanh now has his own homestay in Phong Nha town with three bungalows on the river, 1,000,000 dong per night; T: (0916) 794 506;;

Reviewed by

Cindy Fan is a Canadian writer/photographer and author of So Many Miles, a website that chronicles the love of adventure, food and culture. After falling in love with sticky rice and Mekong sunsets, in 2011 she uprooted her life in Toronto to live la vida Laos. She’s travelled to over 40 countries and harbours a deep affection for Africa and Southeast Asia. In between jaunts around the world, she calls Laos and Vietnam home where you’ll find her traipsing through rice paddies, standing beside broken-down buses and in villages laughing with the locals.

Tours in Vietnam

These tours are provided by Travelfish partner GetYourGuide.

Our top 7 other sights and activities in and around Phong Nha

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Phong Nha Cave

The star park attraction

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A day in Phong Nha-Ke Bang National Park

Scenic loop, historic roads and caves

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Hang En

Camp in the world’s 3rd largest cave

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Paradise Cave

Longest dry cave in Asia

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Bong Lai Valley

Rolling through the countryside

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Botanic Garden & Thac Gio Waterfall

A DIY walk through the national park

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Dark Cave (Hang Toi)

A muddy adventure