Absolutely no!

What showed in the visa approval letter is exactly what you are allowed to enter in. When you apply this letter in advance, you must identify the entry date and exit date. When your letter is approved, the period of time that you can enter to Vietnam is clearly showed. You cannot enter earlier than the entry date, even 1 day or 1 hour. You also cannot exit later than the exit date.

If you want to come earlier than the date showed in approval letter, you must re-apply a new one.

If you want to back later than the date showed in approval letter, you can:

• Apply a new one.
• Extend your visa when you come to Vietnam.
• Pay a fine and exit (not recommended)