A three-day stay for two in Hanoi with hotel, two meals, taxi and tour or activity per day costs US$732.18 (Bt24,831), according to the survey.
Four of the 10 most affordable cities worldwide are in Southeast Asia with Bangkok ranking No 4 ($822), Kuala Lumpur seventh ($914) and Manila ninth ($925).
Ranking second on the worldwide list is Warsaw at $739, while Sharm el-Sheikh was third at $820 and Mumbai rounded out the top five.
The most expensive international city was Cancun, Mexico at $2,019, followed by Zurich ($1,945), New York City ($1,909), London ($1,877) and Punta Cana, Dominican Republic ($1,805).
Trip Advisor compared short city stays in 40 metropolises with costs being registered from March 27-May 5.