There is a lot of confusion about the use of mobile phones in Japan. Please note that the information provided here is intended as a guide only. We cannot be held responsible for charges made by operators or telephone companies. You will find that the charges for using a mobile phone in Japan are expensive and this is especially the case for mobile data (email and internet); We recommend that you disable roaming on your mobile phone to avoid an unpleasant surprise.
A great option is to hire a mobile phone in Japan:
The mobile network in Japan operates on a different system than the rest of the world and until recently no mobile phone from abroad would work. However, with the advent of 3G phones, this has changed. The rule is basically this: if you have a 3G phone, it will work. If you don’t have a 3G phone, you won’t.
Be careful: if you ask your mobile service provider, they can inform you that your phone will work in Japan if it is tri-band or quad. This is not like this.
BLACKBERRY: If you have a 3G Blackberry, it will work in Japan.
If it is not 3G, it will NOT work. Note that the main exception to the above is that some mobile phone contracts DO NOT INCLUDE ROAMING. If your contract does not include roaming, YOU WILL NOT BE ABLE TO USE IT IN JAPAN.
Another option is to hire a SIM card in Japan and put this in your own mobile phone that you have brought from home. Two companies offer this service, Softbank and Mobal Narita (only available at Tokyo Narita Airport). As of September 2010, Softbank is much cheaper for domestic calls within Japan (105 yen per minute). Calls to the US are 200 yen per minute and to the UK 250 yen per minute. Mobal Narita service costs 240 yen for domestic and international calls. The text message with Mobal Narita costs 140 yen each. For Softbank international SMS messages it is 150 yen. The data charges (internet and email) for both are very high. Your phone must be ‘unlocked’ in order to use the SIM card.
Please note that the SIM card must be returned and is not prepaid. You will need to provide your credit card details and then you will be billed for the usage.