The Haiphong Military Command used a crane on the morning of September 4 to lift the bomb from a depth of about 4 metres at 96 Cau Dat Street, Le Chan Ward.
The bomb was then transported to a designated site for disposal, with the entire operation completed safely.
Authorities said the bomb was about 1.2 metres long and 35cm in diameter and weighed approximately 300kg. It was identified as unexploded ordnance left over from the war.
The explosive was discovered on September 3 while workers were excavating the foundations for a new house at 96 Cau Dat Street. The construction team reported the unusual object to local authorities, prompting the Haiphong Military Command to inspect the site and confirm that it was a bomb.
Officials subsequently drew up a plan to recover and transport the bomb for controlled destruction.
For safety reasons, authorities closed an approximately 800-metre section of Cau Dat Street on the morning of September 4. The road is a busy central thoroughfare lined with numerous shops and businesses.
During the war, Haiphong was one of the major targets of US air and naval attacks, particularly in 1972. Bombs, mines and other unexploded ordnance from the conflict continue to be found in the city and surrounding areas.