One of the great things about being in Japan is that it makes a very convenient leaving-off point for travel to the rest of Asia. While Japan may be very expensive to travel through and from, once you get outside of Japan, you will find that many Asian countries are quite inexpensive to travel in. Being that we are all now international travelers, most of the information in this page should go without saying, but just in case you needed a reminder or a checklist, here it is.
Passport IssuesRight, so the first thing you will find that you need to get out of Japan is your passport. Such a small thing that should cause so much trouble! You will need to be sure of two things before you leave Japan: your re-entry permit and any necessary visas for travel.
Re-entry Permit
Traveling abroad from Japan requires you to have you Re-entry permit, discussed in detail here. If you haven't got this, you'll find yourself without a way to get back to work and your apartment when you return from your trip, so get it early and get the mulitple re-entry unless you plan on only leaving once.
Visas
Before you head off, be sure to check your visa requirements. Depending on where you are from, you will likely need a visa for travel longer than 30 days or in the case of China and Vietnam, you may need a tourist visa. Check with the embassy pages of where you plan to go.
This should go without saying, but make a couple of photocopies of your passport and keep them in a safe place while you travel. Keep your passport on you as much as possible. If you can't keep it with you for fear of theft or damage during activities, lock it in a safe deposit box at your hotel and take a photocopy with you.
Travel InsuranceTravel insurance is rarely necessary, but can come in handy, especially if you will be participating in any activities where you might become injured, or if you are traveling in an area where there is known to be some danger of terror or political upheaval. Travel insurance will cover you if you get a tropical disease in Malaysia, pay for your lodging if your flight is cancelled due to weather or other acts of god, and if the worst should happen, will pay for someone to rescue you should you become incapacitated. Travel insurance is recommended if you plan on driving in a foreign country to help cover any accidents you may become involved in. There is a small amount of travel insurance included in your JET Accident Insurance, but its pretty meager. AIU is a good and pretty cheap company with several travel insurance options in English. You can apply for travel insurance at most major international aiports.
Checklist for International TravelSome of the following may not always be applicable, but its always the little things that drive you crazy.