Thu Thiem Tunnel also known as Saigon River Tunnel crossing the Saigon River in Ho Chi Minh City, Vietnam. This is part of the East-West Highway project connecting District 1, Ho Chi Minh City with Thu Thiem New Urban Area.

The tunnel has six lanes of cars, which are submerged beneath the Saigon River (underground river bottom). The investment capital from the Official Development Assistance (ODA) of the Japanese government has reciprocal capital from the Government of Vietnam. The general contractor is a Japanese contractor.

On the afternoon of November 20, 2011, the ceremony to open the Thu Thiem Tunnel was held. On the morning of November 21, Thu Thiem Tunnel was officially opened to traffic after nearly 7 years of construction, connecting the two banks of the river and reducing the load for Saigon Bridge, and as a driving force for the development of the city. The project is rated as the most modern tunnel in Southeast Asia.

Thu Thiem Tunnel is an underground bridge leading to Thu Thiem peninsula, where there are regulations to close and open on time. So vehicles from Hanoi go to Ho Chi Minh City does not know this information should pay attention. The tunnel open daily from 4:00 AM to 11:00 PM.