First, ensure that you are familiar with the rules of the road in Japan – the most obvious being that traffic drives on the left side of the road. The Japan Automobile Federation (JAF) issues a book called “Rules of the Road” in five languages.
You will need to have either an International Driver’s Permit (IDP) plus valid home country license, or a valid Japanese driver’s license. Your IDP is valid for one year from either your date of entry into Japan or the date you got it (written on the IDP), whichever comes first.
Even if you don’t plan on owning a car or driving in Japan, consider getting an IDP to use in case you want to rent a car.
Please be sure to confirm the expiration date, and if you plan to stay in Japan and drive after this time plan to get a Japanese license. Driving without a valid licence is a serious offense and could result in a very expensive fine and/or revocation of your visa – which would mean deportation.
If you will need to get a Japanese license, start preparing as early as possible. For those with a valid foreign license, the conversion process can sometimes take one month or more, even for those from Commonwealth countries.
Drinking and Driving (yes, you too, cyclists!)
Remember that Japan has a zero tolerance law with regards to alcohol and driving (including bicycles!). The legal BAC level is 0.0%. The police have been known to set up random checkpoints, and when drunk drivers are apprehended it is a major story on the evening news. This is especially true when those apprehended are public servants, and even more so when they are foreign residents.
Fortunately, Japan has a system of two-driver taxis called “daiko” (代行) where a second driver can drive your vehicle home for you. The fare is negotiated in advance, and is usually not too far off what a regular taxi would cost, and in many cases is cheaper.