I have a 8330 (CDMA) v4.5.0.131 (Platform 3.4.0.25) through Sprint and need to know if it will work in Japan (Tokyo, Kumamoto, and Fukuoka) as I will be there in February for work. The sprint website said it should but figured I wanted someone with experience to actually answer this.
Seeing that Sprint is a CDMA carrier, I'm not sure if there are any CDMA networks in Japan, and if there are, If they would allow you to activate your curve on their network (not very likely at all). It's not as easy as just swapping a GSM sim card.
Last time I checked with sprint about international travel, they would issue a basic loaner device with a sprint GSM sim card. Not sure if they still do this. If you're due for an upgrade (and with an 8330 you should be close), this might be a great time to get the 9650, as it's a world phone, and will accept international sim cards. Even if you're not quite due, you may be able to talk to customer service about getting an early upgrade and adding the international plan to your account at the same time.
--EDIT--
Looks like DoCoMo is a CDMA carrier, and will allow you to roam on their network ($$?). I would still call sprint and see what that's going to run you under normal use. It may still be cheaper to get the 9650 outright and a japan local sim card to put in it.
