Pitt was spotted driving the motorbike through the city center with Jolie perched on the seat behind him Thursday in a country where virtually everyone travels on the two-wheeled machines. The couple later dined at a popular Vietnamese restaurant converted from an old temple.
Pitt and Jolie arrived unannounced in Vietnam after an earlier surprise visit this week to Cambodia where on Wednesday they toured a former Khmer Rouge death camp, which is now a genocide museum.
The 31-year-old actress, who has an adopted son from Cambodia, also met with officials to discuss a forest conservation project in the country's northwest near Pailin, a former Khmer Rouge stronghold. She has pledged up to $1.3 million over five years for the program.
Jolie's Cambodian son, Maddox, is 5 years old. She and Pitt also have a 1-year-old daughter, Zahara, who was adopted from Ethiopia. Jolie gave birth to the couple's daughter, Shiloh, in Namibia in May.