What is the difference between a single entry visa and a multiple entry visa?

Difference between a single entry visa and a multiple entry visa is:

- A single entry visa is a type of visa on arrival which you only use ONCE within your visa validity to enter and exit Viet Nam. After you left Viet Nam, you must to apply the other visa on arrival if you want to come back.

- A mutiple entry visa is a type of visa on arrival which you can enter and exit Viet Nam many times within your visa validity.