Vietnamese Culture and Tradition 
The local currency of Vietnam is Vietnam Dong or VND. However, most hotels and shops also accept US dollars.
You should change money at official money exchange counters to get the fair rate. Some high-end hotels also offer money exchange services with a lower rate. You should avoid the illegal exchange places such as gold shops
Traveler’s Check
Traveler’s check is a good way to carry money around Vietnam because the exchange rate is fixed and it can be replaced in case of lost or stolen. Checks can also be easily exchangeable in banks.
Credit Card
Most major credit cards such as Visa, Master card and American Express are very usefully in the big cities and some tourist sites too. Those cards can be used in the most mid-range to the high-end class hotels and some luxury restaurants. You can also get the cash advances from ATMs of the almost Vietnamese banks especially Vietcombank.
Banks in Vietnam has developed a large number of ATM networks but it is not recommended to trust completely in ATM because sometimes you cannot get cash from them especially during the Lunar New Year. Furthermore, many shops and restaurants don’t accept credit cards as a payment method.
Vietnam money regulation
You can bring as much as money to Vietnam as you can. There is no limit on amount of foreign currency by tourist but you must declare to the customs. At this time, the minimum amount of money for declaration is USD 7000.
