Which cave in Vietnam has the largest cave passage in the world?

The cave in Vietnam with the world's largest known cave passage is Hang Son Doong. It is located in Phong Nha–Ke Bang National Park in Quang Binh Province, near the Laos border.

The main passage is more than 5 kilometres long, about 200 metres high and roughly 150 metres wide. Its estimated volume is around 38.4 million cubic metres, making it the largest known cave passage by volume. Two collapsed sections of the roof, called dolines, allow sunlight to enter and support trees and other vegetation inside.

Local man Ho Khanh first found the entrance in 1990 while searching for agarwood, but he lost track of its location. He rediscovered it in 2008 and guided a British–Vietnamese expedition to the cave in 2009. Explorers later crossed a 60-metre flowstone wall nicknamed the Great Wall of Vietnam.

A frequent mix-up is calling Son Doong simply the “largest cave” without specifying the measurement. It leads by passage volume and cross-section; other caves can hold records for length, depth or individual chamber area.