A single entry visa allows to enter and exit Vietnam just once during the visa validity. Once you leave Vietnam, even before the visa’s expiry date, the visa automatically becomes invalid. You are required to apply for a new visa if you want to come back to Vietnam.
For example, if you apply for a 1-month single entry visa, you are allowed to enter and exit Vietnam only ONCE from your pre-registered arrival date & the visa will automatically expire within 30 days from your pre-registered arrival date.
A multiple entry visa allows to enter and exit Vietnam multiple times during the visa’s validity. It means that with this kind of visa, you can leave then re-enter the country during the visa’s validity without applying for a new one.
For example, if you apply for a 1-month multiple entry visa, you are allowed to enter and exit Vietnam multiple times within 30 days from your pre-registered arrival date.
Note for a multiple entry visa on arrival, you need to select the port of arrival for your first arrival to pick up your visa there. After picked up the visa, you can re-enter Vietnam at any ports you want as long as your visa still valid.
