Verify the expiration date of your current passport. If it expired within the last 12 months, or is still current, you are eligible to renew your passport by mail.
Download the renewal forms from the Vietnamese Embassy website. The online instructions are only available in Vietnamese. If you do not speak Vietnamese, you will need to e-mail or call the embassy and request that they send you the correct forms.
Fill out the renewal form. You will need to submit a copy of your passport and any other pertinent documents with the form.
Have a new passport photo taken. It must be less than 12 months old and be 2"x2" in size, taken against a white background in the full frontal face position.
Mail your request along with the correct form, your photo, renewal fee and other supporting documents, to the Embassy or Consulate, whichever is closer to you. Mail your application by USPS Express mail or Fedex, so that you have a tracking number. Keep the tracking number.
Allow 30 days for the embassy or consulate to process your request. If you have not received a response after that time, call or e-mail them directly.