Military officers in the northern port city of Hai Phong successfully removed a bomb weighing around 100 kilograms that had been dragged up by the anchor of a cargo vessel on December 18.
The ship pulled anchor on December 17 afternoon, carrying along a rusty bomb of more than one meter long from the bottom of the river.
All crew members were moved from the ship, and military officers spent a day moving the bomb to a safe place.
An officer said the bomb was one of thousands dropped by the U.S. during the Christmas Bombings over Hanoi, Hai Phong and several northern provinces between December 12 and 30, 1972.
Unexploded ordnance still covers a fifth of Vietnam and explosions occur frequently, killing more than 1,500 people every year and maiming and injuring 2,200 more, according to official data.