There is no GSM network in Japan, its either CDMA, W-CDMA (UMTS), or PDC. The network that is compatible with most international handsets is currently UMTS. So you can use any UMTS 3G set while roaming in Japan. Last time when I went there we can still use WAP over 3G, MMS, and SMS. If you bring a GSM only set, then it is as useful as a camera, mp3 player, portable game & phonebook only.

Below is the roaming charge when I was there last year (with Vodafone KK, not sure how it will be with Softbank though). I was a bit doubfounded since I used lots of SMS (abt 20) and MMS (abt 3-5) there, yet Maxis charged very less...

Edit: Found the reason - The SMS / MMS to Malaysian numbers were calculated at normal non roaming rate. The 1 SMS was a message that I sent to a friend in JPN.



This post has been edited by Volfeed: Dec 2 2006, 12:16 PM