Karnaphuli Tunnel

The Bangabandhu Tunnel is an underwater road passage beneath the Karnaphuli in Chattogram District. The two tubes run parallel, separated by a central dividing wall, and offer a total of eight lanes for traffic in both directions.

Construction began in 2017, drawing from Chinese tunnel projects in Shanghai. Traffic started rolling through the two tubes under the river in October 2023.

The tunnel links both banks of the river directly for the first time, allowing drivers to cross without using the ferry service. Before its opening, the river remained a natural barrier for continuous road traffic.

Vehicles drive at speeds up to 80 kilometers per hour (50 miles per hour) and save roughly 40 kilometers (25 miles) on the route to Cox's Bazar. The crossing takes just a few minutes and replaces waiting time at the ferry.

The deepest point sits roughly 31 meters (102 feet) below the river surface, while the shallowest reaches around 18 meters (59 feet). It forms part of the Asian Highway and connects the route from Dhaka through Chattogram to Cox's Bazar.