What do I need to do if I want to travel outside the country during my stay in Japan?
Until recently, you needed a re-entry permit if you were planning to travel abroad. However, the changes to the Alien Registration system have made things much easier.
As long as you are planning to return within a year of your departure date, you do not need a re-entry permit. Just make sure you bring your Resident Card (or Alien Registration Card) and your passport.
Before you leave the country, you`ll fill out and hand in a disembarkation card for reentrants, and then you`re free to travel. Just make sure you have any necessary visas prepared for the country that you are visiting..