Check the expiration date on your Vietnamese passport. If it is still current or if it expired within the past 12 months, it is eligible for renewal by mail.
Download the required forms from the Vietnam Embassy website. (See Resources.) Go to the passport section, which is only available in Vietnamese. If you do not speak Vietnamese, write or email the Vietnamese Embassy or Consulate to request the forms required for passport renewal (see Resources). Include your address and the Embassy or Consulate will mail you the documents.
Complete the passport renewal documents. Make a copy of your Vietnamese passport, and the forms which prove your legal residency in the United States, such as your green card.
Get passport photos taken at a local pharmacy or U.S. Post Office. Make sure the photos meet all the requirements: 2 inches by 2 inches, color with a white background and taken within the past year.
Mail the renewal documents. Send them, along with your original passport and a copy of your legal residency forms, to the Embassy or Consulate. Confirm the renewal fee with the Embassy or Consulate before you return the forms.
Allow one month for processing. Contact the Embassy or Consulate if you have not heard from them within that time frame to make sure they received your passport and all required documentation.