An International SIM gives your phone access to multiple cellular networks around the world. This allows travelers to use their phones overseas without having to pay the high costs of roaming services from their local provider.
With an International SIM you:
International SIMs work like your regular local SIM card, they connect to nearby cell towers which then transmit your information to the correct recipient. Providers of International SIM Cards, like Telestial, have agreements with numerous local telcos who own and operate cell towers, that way you can easily connect to a network in Paris, Sydney, Buenos Aires or even Timbuktu.
To use an International SIM Card your device must be travel-ready: