Travellers' cheques now is more difficult to use since passport are requested to show when cashing. And remember about second signature rule when using Travellers' Cheques.

You can change cash and travellers’ cheques at exchange desks in big hotels, shops licensed to sell gold and at authorised foreign exchange banks in the main cities. Among the banks, Vietcombank usually offers the best exchange rates and charges the lowest commission (around 1-2%). Note that commission rates are slightly lower if changing travellers’ cheques into dong rather than dollars. Vietcombank does not levy commission when changing dollars cash into dong, though some other banks do. It’s worth bearing in mind that you get a slightly better exchange rate for $100 and $50 notes than for smaller denominations.

Outside the main cities and tourist areas, authorised foreign exchange banks are few and far between. So if you’re heading off the beaten path, stock up with enough cash (dollars and better dong) to last the trip. Wherever you are, you’ll always find someone willing to change dollars cash into dong, though rates will vary.

When departing, change any Dong back to US dollars.If you have a lot of dong left over when leaving, can change back to the currency you entered with by showing the yellow customs slip that you were given on arrival. The amount you take out must be less than the original amount you brought in. But it's better change back into Dollars when in the city.