From  Sapa - Cat Ba number 1 Buses

Sapa - Lao Cai - Cat Ba - Hai Phong bus route is approximately 799 km in length. On average, there are about 4 bus schedules on this route and  bus travel time may take from 8h20 to 20h30, 21.20pm by 1 bus companies: Ket Doan. Duration is about 11 hours.