There has been some confusion whether you will be be able to use a local GSM micro-SIM in the CDMA iPhone 4S (which also comes with the micro-SIM card slot since it is a world phone) while travelling internationally, so that you can pay cheap local rates instead of the expensive international roaming rates.
Until now, we thought that it was not possible based on the iPhone FAQ on Apple’s website, which came as a major disappointment to some of our readers, especially as many felt it defeats the purpose of Apple launching iPhone 4S as a “world phone”.
But MacWorld reports that it will depend on your carrier. It looks like Sprint plans to sell the CDMA iPhone 4S with its micro-SIM slot for GSM unlocked, while the Verizon CDMA iPhone 4S can be unlocked by request after 60 days.
Sprint plans to sell the iPhone 4S with its micro-SIM slot unlocked; Verizon’s will be initially locked, but if you’ve been a customer in good standing for 60 days, you can call Verizon and ask for an “international unlock.” (A Verizon spokesperson told me that this is Verizon’s standard policy for all world phones—it’s just the first time it’s manifested itself on an iPhone.)
This should come as good news for users who travel internationally. This can be another advantage of buying a Sprint iPhone 4S compared to other AT&T (which will be locked to AT&T’s network and will be able to roam internationally on AT&T’s partner networks) and Verizon (as it keeps the international roaming disabled for the first two months and could be more if it doesn’t consider you as a customer in good standing).