I can change the port of entry that I have choosen when I applied e visa?

Dear Italivi,

Thanks for your attention on our service.

In this case, you can estimate your arrival time to apply for Vietnam Visa. 

For example, you apply for 1 month Visa and you put your arrival date in the application form is on Jul 1. So your visa will be valid from Jul 1 to Aug 1 and you are able to arrive any date within this period time.

Please feel free to contact us for any question

Thanks,

Lucy