What is a SIM Card?

SIM cards, short for Subscriber Identity Module, are the 'brains' of mobile phones using the GSM (Global Service for Mobile Communication) platform. SIM cards are available on a pre-paid or contractual basis. If you have a tri-band GSM phone, you can use the same phone and just change the SIM card for whatever country you are in. First you will have to ask your wireless provider to "unlock" your phone so that it can use other SIM cards. With a local SIM card, you will not be "roaming" so you can take advantage of the lower, local rates, as well as having a local number. SIM cards are also available for international use if you will be traveling to several countries, but rates may be higher if you have to "roam" outside of one calling area. You can buy SIM cards over the Internet at Cellular Abroad.