Originally Posted by
msb0b
Most of ATT's 3G phones don't have the WCDMA 2100 band necessary to roam on NTT DoCoMo and Softbank's networks. iPhone 3G, Treo and HTC models do have the proper band. The non-smart phones from Nokia, LG and Moto don't.
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The first 3G phone I used in Japan was an old Motorola A835 unlocked from the UK 3G system. The current phone I am using for Japan travel is a Nokia N73 factory unlocked model. My colleague had used Nokia 6630 in Japan. I am not sure any of these can be called "smart" phone or not.