I have an AT & T Samsung S4 (locked). Will a sim card for Vietnam work ?

[AC Question]

If sim card exchange works will my Contacts be saved?

 

[anon(632115)]

No other sim will work unless you get the device sim unlocked so you will need to contact AT&T about this. You will only get 2g & 3G in Vietnam and lastly if your contacts are stored on your sim and you use a different one, they will be lost. To transfer to your device Samsung Galaxy S4 - Copy contacts between your SIM and your phone