The Ham Rong Tunnel project will connect National Highway 4D with Provincial Road 152 and is scheduled for construction between 2026 and 2029.
The 1.4-km route includes a 1.2-km tunnel through Ham Rong Mountain. It will feature two tunnel tubes, each carrying two traffic lanes, together with four-lane approach roads and a bridge linking the southern entrance to the existing road network.
The project also includes supporting infrastructure such as power supply, lighting, ventilation, drainage, fire protection and traffic management systems.
Once completed, the tunnel is expected to provide a direct link between the two roads, reduce traffic through central Sapa and improve connectivity across the town.
Sapa, one of northern Vietnam's best-known mountain destinations, receives more than 4 million visitors each year. Local authorities say rapid tourism growth has outpaced the town's transport infrastructure, leading to frequent congestion during weekends and public holidays.
The project is intended to ease pressure on the town centre while supporting future urban and tourism development.