<SPRINT> SIM Card question

[mikejones13]

You can always buy a pre-paid sim card and use U.S. GSM network, but you have you buy one or have a service with one.

[kilmarac]

Originally Posted by mikejones13

You can always buy a pre-paid sim card and use U.S. GSM network, but you have you buy one or have a service with one.

Why would I want to do that, or are saying that for japan. Sorry if I seem like a noob. Well.. I guess I am a noob as far as GSM and international stuff goes. First time ive had a phone that would do it, and first time Im traveling internationally.