“It Would Be Like Finding A Lump On Top Of Mount Everest That Would Make It Another 1000 Meters Higher.”

The title pretty much sums up the case of the largest cave on Earth – Son Doong. Upon its first discovery back in 90s by a local man and the official discovery and exploration back in 2009, Son Doong shocked the world with its incredibly gigantic size, went on to become the biggest cave on the face of the planet and after a very special event in early April 2019 – Son Doong’s underground river diving expedition, the results make it official that Son Doong is actually bigger than we thought!

This surreal revelation has certainly generated hysteria among adventure enthusiasts, travelers, nature lovers and professional cavers worldwide! Read on to find out all the interesting details about this milestone.

Diving Expedition To The Underground River Of Son Doong – Making History!

In the first week of April 2019, the underground river inside Son Doong cave was dived to a length of -77 m and this made history as the deepest cave dive ever conducted in Vietnam! It was quite a challenge to make more progress, owing to the terribly low visibility of only 2 meters! The beginning of this sump was measured at an astounding depth of -93 m and deepened further ahead.

To be able to dive deeper into the Son Doong Cave, the divers would need to plan a -120 m depth dive and for that, they’ll need to be using a special mixed gases of helium and air. When a dive is to be executed at such a major depth, the level of the challenge dramatically increases and the dives go on for up to 5 hours, which is predominantly done to allow proper decompression.

Due to the use of compressed air, the divers couldn’t dive any deeper as it would expose them to significant risks underground. When spoken to, the diving team said they’ll mostly be coming back in April 2020 to reattempt the dive with all necessary equipment.

About The Son Doong Cave – A Unique Wonder Of The Cave Kingdom

The world’s largest cave, Son Doong, sits majestically in the Phong Nha – Ke Bang National Park, which is one of the best places in Vietnam and also one of the top natural world heritage sites in the world. The jaw-dropping size of Son Doong leaves explorers awestruck and makes them feel like they’ve entered an extraterrestrial world under the surface of the Earth. One of the top reasons to visit Vietnam is a chance to explore this cave by joining the adventure of a lifetime – Son Doong Expedition. Oxalis Adventure – a professional adventure operator in Vietnam which is based in the Phong Nha – Ke Bang National Park as well and is the only qualified (in safety and conservation) official tour operator in the world allowed to conduct expeditions to Son Doong.

This cave is almost 3 million years old and is the ultimate cave experience for adventure and exploration enthusiasts worldwide! It’s not just a cave, but a different and unique underground environment. Son Doong is so huge and has its own jungle, river and even its own climate! It was officially explored in 2009-2010 by the British Cave Research Association (BCRA).

One of the things that put Son Doong at the summit of the top caves to visit in the world is its enormous size; at almost 6km long, with sections reaching up to 200m tall and 150m wide, Son Doong Cave 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 meters, this comfortably surpasses Deer Cave in Malaysia, which was considered to be the previous record holder. After having established an official connection with Hang Thung, another 1.6 million cubic meters of volume would be added to it; this means that Son Doong would enhance its position of the largest cave in the world and continue to prove that it still keeps its mysterious charm alive and remains a secret.

Trending On The News – The World Is Talking About Son Doong!

This mind-blowing diving expedition in the underground river of the world’s largest cave – Son Doong has caused quite a stir worldwide and has shocked experts, nature lovers with yet another thrilling secret. All major news channels are talking about the trailblazing diving expedition and the fact that Son Doong is still the biggest cave on our planet, but is in fact bigger than we thought! Everyone is also sharing their excitement about what other incredible facts about Son Doong’s size would be revealed when the diving team returns in April 2020 and reattempts the dive.

One of the world’s most renowned media channels, CNN Travel recently released an article about this glorious discovery and also shared a video showing the world the might of the Son Doong cave. CNN also got a chance to interact with Howard Limbert, who was the leader of the first caving team that discovered and explored the Son Doong cave and he is also the Technical Director of Oxalis Adventure.

When in conversation with CNN Travel, Howard Limbert exclaimed that “It would be like finding a lump on top of Mount Everest that would make it another 1000 meters higher.” He also added that “Any cave in the world could comfortably fit inside Son Doong when it’s connected – the size is just outrageous!”

Popular websites like Travel & Leisure and News.com.au have called this a ‘groundbreaking discovery’ and have been widely spreading the word through interesting articles and videos, along with giants like MSN and Kids.com.au expressing their awe at the extraordinary discovery of Son Doong Cave’s outrageous size. The entire science and travel news community can’t contain their excitement about Son Doong and Hang Thung’s mysterious underground connection, what’s to come when the divers return in 2020 and are brilliantly telling the world about the wonders hidden inside the Phong Nha – Ke Bang National Park of Vietnam.

Exclusive Journey To The World’S Largest Cave – Hang Son Doong!

This incredible Son Doong Cave Expedition will give you a wonderful chance to explore the world’s largest cave and exit via the Great Wall of Vietnam. This is the only tour available of Son Doong Cave by the official tour operator Oxalis Adventure Tours.

This exclusive journey requires more than 25 porters, safety advisors & guides. You will explore the entire length of Son Doong Cave, Hang En Cave, and visit Ban Doong ethnic minority village.

Imagine trekking straight into the depths of the world’s largest cave which can fit a Boeing 747 flying through the largest passage, on an expedition unlike any other. Son Doong Cave is a masterpiece of nature with otherworldly landscapes, enormous stalagmites and statuesque stalactites – hanging from the ceiling and rising from the ground like an alien species. The real jungle inside the cave will amaze you in every way, while misty clouds envelope the scene. The fossil passage will give you the opportunity to understand the formation of this ancient limestone.


  • Climb the Great Wall Of Vietnam
  • 2 nights camping inside Son Doong Cave (largest cave in the world)
  • 1 night camping in Hang En Cave (third largest).
  • Portable lighting equipment to capture stunning photographs
  • 25km of Jungle Trekking and 9km of Caving
  • Visit Ban Doong Ethnic Minority Village

An adventure from start to finish, you will use ropes to climb into the entrance, and climb up the Great Wall of Vietnam, a calcite wall totaling 90m in height. You will always be under the guidance of the Oxalis safety team.

The Expedition is not a race, so you should not expect to rush on this tour. There will be plenty of time for photography and to explore the cave. However, all adventurers are expected to be fit, and have some previous trekking experience (not necessarily climbing or caving experience).

There are places remain available for trips departing in 2020 and 2021. Please make your reservation here or contact us at [email protected] for details.

Best Safe Hotels in Phong Nha

Below, some hotels we would recommend in Phong Nha with the best COVID-safe measures. All staff members have been fully vaccinated, ensuring your safety while exploring Phong Nha.

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Whether you prefer long treks, camping in a cave, sleeping under the stars in the jungle, swimming underground in river caves, explore the huge dry caves or just taking an exploratory day trip, Oxalis Adventure Tours can provide the right amount of adventure just for you.

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