Getting to Phong Nha
Airplane: Currently, the closest service is via Vietnam Airlines to Dong Hoi, check their website for latest fares and flight times.
Train: Several arrivals and departures at Dong Hoi daily from as far away as Hanoi and Ho Chi Minh City, only a few hours from Hue.
Bus: From Dong Hoi to Phong Nha you can get a local bus. It departs at 14:00 from Nam Ly bus station. The bus back to Dong Hoi leaves Phong Nha at 8:00, so you have to either stay overnight or try to go back with one of the tour buses.
Motorbikes: Motorbikes can be rented for 150,000 VND from hotels in Dong Hoi. It takes about 1 hour via a highway that has little traffic: the Phong Nha cave is about 45 km from Dong Hoi and the Thien Duong (Paradise) Cave is about 70 km from Don Hoi. Taxis: can be hired from hotels/resorts, airport or train station in Dong Hoi. About 1 hour on a highway with cars, oxcarts, motorbikes, buses, trucks. Tours are available from Hue. Hotels in Dong Hoi can arrange day trips to the park