Trains run from Hanoi to Yen Bai and take about about five hours. From Yen Bai you will have to make your own way to the lake by xe om or taxi to reach Thac Ba Lake.
If coming from Sapa, you can also travel by train to Yen Bai from Lao Cai.
Buses run to Thac Ba Lake from My Dinh bus station in Hanoi. Take the Lao Cai bus and get off in Cat Lem district, about four hours in. From here you’ll need to take a xe om (motorbike taxi) or taxi, costing around 150,000 VND and 400,000 VND respectively.
By bus from Sapa, it's on the Lao Cai to Hanoi (My Dinh) route.
If you’re heading to Thac Ba Lake under your own steam, first head towards Noi Bai airport but take the big turn left four kilometres before the airport, signposted to Phuc Yen. Before hitting Vinh Yen, turn left towards Viet Tri then after Viet Tri town go through Den Hung–Phong Chau and Doan Hung to reach Cat Lem market place. Thac Ba is about 25 kilometres further on.
Most of the journey is on main roads but the last hour or so traverses villages and as you get closer the road gets much bumpier. It's safest to travel by daylight due to the high number of road hazards: not just holes in the road and other motorists but also chickens, dogs and the occasional buffalo.
If travelling by bike or private car from Sapa, the journey is 200 to 250 kilometres, depending on where on the lake you are aiming for. Drive down to Lao Cai, cross the river and find the AH14 (also called the QL70), which is the main Hanoi road. You can follow this all the way along the western edge of the lake.
An alternative, but longer, route is via the QL32, which runs from Sapa up towards the Hoang Lien National Park, eventually cutting across to Yen Bai on the QL37, but we can’t vouch for the road quality.
La Vie Vu Linh Ecolodge can provide more detailed directions or arrange transport if you are heading there.