I am the owner of a carrier unlocked (Italian) iPhone 3G and will be coming to Japan for 10 or so weeks on a tourist visa. As I'd love to be able to use it during my stay, I would like to ask what my options to do so are. First of all, is it really illegal/impossible to buy a prepaid SIM card instead of renting one? The only reasonable option not requiring Japanese ID I found so far is Softbank's SIM rental (http://www.softbank-rental.jp/en/phones/sim3g.php), and even this requires shelling a good 50 EUR over the period BEFORE service charges. Does anyone know of alternatives? (Is AU still CDMA only or do they have a compatible UMTS 3G network? Does DoCoMo rent/sell SIM cards to foreigners?) Also, if I did decide to go down this route, what exactly would I be able to use apart from voice calling? To the best of my knowledge Japanese handsets use e-mail instead of SMS/MMS, but the pricing details for the softbank rental include SMS and MMS charges. Do Japanese phones just refer to MMS as email or is Softbank's back end translating between the two? In practice, how would I send and receive mail from other Japanese cellphones and how much would it cost me? (I do use my Gmail account with the iPhone but it doesn't notify me of new messages instantly the way SMS/MMS do) Finally, is there any way of getting a data plan on rented SIMs? The thought of paying 20+ EUR per megabyte with no ceiling and the phone company having my credit card details scares the hell out of me.