I think we need a rule for these kinds of threads - everyone who answers the question should disclose his perspective. I think most people would fall into one of the following groups:
(a) I live in Japan and use a local phone, so I don't have recent, personal experience of the challenges of communicating while visiting Japan from abroad
(b) I live outside Japan and have never been to Japan, but I've used my cell phone in the US and Europe, so I guess I know all about roaming
(c) I live outside Japan and recently travelled to Japan and worked out a way to stay in touch while in Japan that was satisfactory to me
(d) I am a global telecommunications expert
(e) I don't know my arse from my elbow really, but I like to pontificate
If we all disclose this information, it should be easier for people reading the thread to decide which answers to trust.
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Disclosure - I fall into category (a)
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My contribution is in three parts:
(1) If you need to use your US number while you are in Japan, then your best bet is to follow the advice on the AT&T web site:
http://www.wireless.att.com/learn/en...outh-korea.jsp
You will see that your Motorola handset is
not one of the 3G 2100MHz devices that AT&T touts as usable in Japan. Maybe free101girl knows better.
(2) If you don't necessarily need to keep your US number - you just want a local Japanese phone that can receive incoming and make outgoing calls - then you can find information in the other threads about several companies who will rent you a local phone in Japan. (Some of these companies have booths at Narita Airport. Some deliver the phone to your hotel. Some are more expensive than others. Some can tell you what your phone number will be before you arrive in Japan. All this is discussed in in other threads)
(3) If you're here for a week or so, you may find it cheapest to get a Japanese friend to buy you a prepaid phone to receive incoming calls - and then make your outgoing calls from public phones (with a calling card) or via an internet telephony solution such as Skype.