Japan is a diverse country for telecommunications.
There are a number of providers in Japan, several of them offering GSM services, however there are many other network types operating including CDMA and the "Personal Handy-phone System". This can make it difficult to find a SIM card compatible with your phone in Japan, so you may need to do some research.
The providers listed on this page offer 2G and 3G GSM networks which may be compatible with your phone.
Buying a SIM card in Japan
There are no known restrictions on overseas visitors buying a SIM card while travelling to Japan.
We're not sure whether any providers for Japan offer prepaid mobile phone services for overseas visitors. Leave a comment below to let us know your experiences!