The easiest way to ensure no data roaming charges while traveling is to place a U.S and/or international data block on your account.
This will prevent you from being able to use the Internet on your device sand can be done for you at TELECO.
A second option would be to turn your data off in the settings of your phone.
In order to access the Internet this setting would have to be turned back on.
Contact us if you need more information. We want to help.