Foreigners intending to stay in Japan for longer than 90 days are legally obligated to register with their local municipal office (listings for municipal offices can be found here: http://www.metro.tokyo.jp/ENGLISH/LINKS/links1.htm) within 14 days to obtain an official Alien Registration Card. That said, many foreigners make the trip to the municipal office much earlier because an Alien Registration Card is required for a number of “daily life” instances including opening a bank account and purchasing a cellular phone. Once you receive your Alien Registration Card, you are required to carry it with you at all times as it is your official national identification. Foreigners that have not applied for an alien registration card must, by law, carry their passports with them instead.
The application process is simple – all municipal offices have a counter where Alien Registration Cards are processed, and most offices have some English-speaking staff. Application forms are available at the counter and all that is required is your passport and two recent (4.5 cm x 3.5 cm) photographs. Some municipal offices also have a photo booth in the event that you are unable to get your picture taken ahead of time.
As your Alien Registration serves as your official ID, changes to the registered content must be reported to your municipal office within 14 days of the change. While your municipal office can provide specific detail on change of content requirements, notification must be made when changing your name, address (if within a new municipality you would visit that area’s municipal office), and visa status, among other content.