I am Vietnamese who has a 2 year old son. He is Thai. He has his own passport.

So far, I travelled with my son back and forth to Vietnam. The immigration officer in the airport sometime ask me for his birth certificate (as current, his surname and my surname is not the same). Next summer, I would like my son to travel with my mom (who is Vietnamese) to Vietnam. I would like to ask if anyone has experience about this and which document should I prepare (i.e., kind of a letter from parents allow children to travel with grandmom)? Where should I go to make the document legal (i.e., amphoe where I am staying or Vietnamese embassy?)

Thank you for your kind reply in advance.

Best

When traveling with the child, just like you she can be questioned. What she needs to bring with her is the birth certificate of the child, a copy of the ID-cards of both parents and a simple note stating that she has your permission to travel with the child, maybe also giving a telephone number. You could hve the letter stamped by the amphur, but might not be necesarry.

There are extra checks because of ant child trafficking measures, which is their main concern.