A Subscriber Identity Module, or SIM card, is a portable memory chip that is used in some models of cell phones to store data such as user identities, international phone numbers, address books and phone usage records. SIM cards are used with carriers that operate on the global system for mobile communication, or GSM, network. Sprint phones use Code Division Multiple Access (CDMA)—a form of wireless multiplexing, in which data can be sent over multiple frequencies simultaneously, optimizing the use of available bandwidth—thus they are CDMA-based, not GSM-based, and cannot use SIM cards. The exception is Sprint's PCS International Roaming plans, which use GSM-based international phones. These phones require a SIM card to be inserted before they can be activated. With these plans, the SIM cards are required for logging phone usage to calculate billing.
Shop for an international phone carried by Sprint. You can do this at any brick-and-mortar Sprint store or online on the Sprint website. A link to Sprint's list of international phones can be found in the Resources section. If you are buying any Sprint phone that is not on this list, you do not need to buy a SIM card.
Purchase one of Sprint's GSM-based international phones and the requisite plan. When you buy the phone, you are also buying the Sprint SIM card, which is included and preinstalled.
Contact Sprint Worldwide Customer Service if your preinstalled SIM card becomes damaged or lost, as you will need to find out what restrictions may apply to your replacement SIM card options for your mobile phone model. Some phones may be able to use any SIM card, which can be purchased affordably anywhere cellular accessories are sold. Others may have more restricted options. Call Sprint Worldwide Customer Service at (888) 226-7212 from the United States and at (817) 698-4199 from outside the United States. A customer service representative will be able to tell you what your SIM card replacement options are.