Phong Nha is a district in Quang Binh province, Vietnam. It is best known for its magnificent and mysterious caves, some of which date back millions of years. The most famous is Paradise Cave (Thien Duong), and Phong Nha Cave (Son Doong). There are also hundreds of smaller limestone cave systems throughout the region. And getting to most of them requires an amazing hike through the Vietnamese jungle.

How big is the cave system at Phong Nha Ke Bang National Park?

Phong Nha cave system - biggest cave in world

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The Phong Nha Cave system is huge, much bigger than Mammoth Caves in Kentucky. It is the largest cave in Asia and also one of the most complex cave systems in the world, with more than 186 miles of underground passages and chambers. The caves are mostly made up of limestone formations, formed over millions of years by the Chay River, which runs through the area. The cave system is also home to numerous fossils, stalactites and stalagmites, and a variety of other geological formations. Additionally, the national park is also home to an impressive array of fauna, including bats, birds, fish and several langur species.

The largest cave in the system is Son Doong, which measures more than five miles long and is 656 feet high and 492 feet wide at the largest point. It is believed to be the world’s biggest cave, even surpassing Deer Cave in Malaysia and more well-known caves in Laos.

How to see the caves

boat tour of phong nha

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The only way to see the Phong Nha Caves is through guided tours by local tour operators. Tours range from easy, overnight camping trips to multi-day treks that explore some of the area’s more remote caves. The most popular tour is Son Doong Cave, which involves a five-day trek through the wild and stunning landscape of Phong Nha-Ke Bang National Park. Other popular tours include Hang Toi, Dark Cave, and Paradise Cave. All tours are led by experienced guides, who will provide safety instructions and a briefing before entering the cave systems.

If you want to camp inside the caves, you’ll probably do so inside a cave called Hang En, which is likely the one you’ve seen in photos. Trips to this cave are usually not available in October and November as that’s the peak of the rainy season in that part of Vietnam.

Reputable tour operators to travel with include Oxalis Adventures, a locally owned company that employs locals for nearly all roles, or you can see the Phong Nha cave’s underground river via Phong Nha Cave Tours, which travel into the cave by boat.

Where is Phong Nha-Ke Bang National Park?

campingin phong nha

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The caves are in Phong Nha-Ke Bang National Park, in Quang Binh Province, Vietnam. The park encompasses an area of 342 square miles and is home to a variety of rare wildlife, including the endemic Cat Ba langur monkey. The park was declared a UNESCO World Heritage Site in 2003 and the caves were discovered in 2005.

The closest major tourist town is Dong Hoi, known for beaches and a rather laidback seaside vibe. From Dong Hoi, it’s about an hour north to the park. Most tours include transportation from Dong Hoi, and while you can technically see some of the smaller caves in one long day trip, it’s best to do a multi-day trip — or at least an overnight camping trip — so you have plenty of time to explore the caves.