If you plan to do any driving while you are abroad, get an International Driving Permit (IDP) from your local Automobile Association or motor vehicle department before you leave. In many countries, these are valid for only one year, so there is no sense getting one too far in advance of your departure. However, some countries will issue IDPs that remain valid for several years – it depends on where you live. Make sure your license states that it is valid for motorcycles if you plan to ride one.
In Vietnam, you can drive. It is recommended that you rent a car, because it will be safer. Many travelers may find traffic in Vietnam difficultly.