Traveling to Vietnam in HCMC Unlocked Phone/Sim Question [closed]

First thing is to check to make sure your phone will work overseas. The USA uses different frequencies for voice calls than Asia, but the phones they market as "tri-band", "quad-band" or "international" will work outside the states. Many of the newer smart phones and phablets already cover the full spectrum, but check to be sure.

Then pick up a pre-paid SIM with a data package when you arrive in HCMC. Data roaming on ATT will be expensive. I am not up to date on the best packages currently offered, perhaps someone else will jump in with specific company recommendations.