Phong Nha Ke Bang National Park

Phong Nha-Ke Bang: The World’s Largest Cave System, Practically

Phong Nha-Ke Bang National Park in Quang Binh province, central Vietnam, contains more than 300 mapped caves in a 123,000-hectare block of Annamite limestone karst. The caves formed over 400 million years - among the oldest karst in Asia. Three of them are large enough to have their own weather systems. Son Doong, surveyed in full only in 2009, is the largest known cave passage in the world by volume: 5km long, up to 200m wide, 150m tall in the largest chambers, with a jungle growing from the cave floor where the roof has collapsed.

Son Doong: what it takes to go

Oxalis Adventure is the sole licensed operator for Son Doong expeditions. Tours run for four nights/five days and cost USD 3,000 per person. Group sizes are capped at 10. Dates for the following year are released in late January and sell out within hours. If you want to go, check the Oxalis website on the January release date and book immediately. The price does not negotiate down. The physical requirements are real - you climb a 90m wall of calcite flowstone and wade through underground rivers. It is not suitable for those with mobility issues or fear of heights.

Cheaper cave tours do not give access to Son Doong. If you are booking a “Son Doong experience” for USD 100-200 from a guesthouse, you are going to a different cave.

The accessible caves

Paradise Cave (Thien Duong) is 31km from Phong Nha town and open to day visitors (VND 250,000 entry). The accessible section is 1km long; the full cave is 31km. What’s open is still impressive - stalactite formations up to 20m tall in cathedral-sized chambers. A wooden boardwalk guides visitors through the main section. The cave stays at around 20 degrees Celsius year-round; bring a light layer.

Phong Nha Cave itself, a 1.5km river cave, is reached by boat from the Son River dock near town (VND 350,000 for a private boat, 1-hour round trip). The boat travels through limestone chambers into the cave on illuminated green water. It is shorter and more crowded than Paradise Cave but the river approach is distinctive.

Dark Cave, 8km from town, allows kayaking and zip-lining into a cave where you can swim in an underground lake and wallow in mud. It is less scientifically impressive than Paradise Cave and more fun; the group that ran it until recently collapsed commercially, so confirm current operators before booking.

Phong Nha town

The village of Phong Nha (Son Trach) has grown rapidly since the park gained UNESCO status in 2003 and again after Son Doong publicity reached Western audiences around 2014. It is now fully set up for tourism with a main street of guesthouses, restaurants, and tour offices. Easy Tiger Hostel on Ho Chi Minh Road has decent rooms from USD 8-15 per night and a reliable tour-booking service. Bomb Crater Bar, run by a local family in a shell crater from the American war, is the best known evening spot and worth visiting for the setting.

Bun bo Hue - spicy beef noodle soup from the Hue culinary tradition - appears on most restaurant menus and is better here than in Hanoi. Banh mi from street stalls costs VND 15,000-25,000.

Getting there

Phong Nha is 52km northwest of Dong Hoi, the nearest city with an airport. Dong Hoi has direct flights from Hanoi (1 hour) and Ho Chi Minh City (1.5 hours). Shared minibuses and taxis run from Dong Hoi to Phong Nha regularly (about 1 hour, USD 5-10). The Reunification Express train stops at Dong Hoi on the Hanoi-Ho Chi Minh City route.

The park is open year-round but February through August has the most reliable weather for cave visits. Heavy rain from September through November can flood cave entrances and close some tours.