Hi Colleen! How did this work out for you? I, too, am in San Miguel under Telcel (and sometimes another carrier) and want to make sure there will be no surprise charges. I received three texts when I arrived with information on roaming support, overage costs if I exceed my allowance of minutes and messages and overage costs for an additional 1GB. I think this means I'm covered and shouldn't have any surprise billings unless I go over, but I am checking to see how this has worked for others. Gracias!