In general, laws regarding automotive seat belts in Japan are fairly simple and straightforward. However, a few points should be kept in mind by the driver, as she is the one likely to penalized.
Japanese law requires that all vehicle occupants wear seat belts; this includes back-seat passengers and children. Prior to April 2008, officials urged drivers to try to get back-seat passengers to use their seat belts, but drivers these days are responsible for ensuring that all passengers, regardless of age or location in the vehicle, have their seat belts securely fastened.
Not everyone in Japan is required to wear a seat belt, however. Pregnant women and people with disabilities that make it difficult for them to fasten their belts are exempted.
Expressway vs. Non-Expressway
The imposition of penalties is limited to violators on expressways---and, again, only the drivers can be penalized. As a result, passengers on tour buses are routinely asked by their driver to fasten their seat belts when the bus is about to enter an expressway. Due to a lack of public support for the regulations, violators on local roads and surface roads receive only warnings.
Drivers carrying passengers not wearing seat belts have a penalty point added to their driving record; six points results in suspension of their license, while 15 points gets it revoked. Passengers not wearing seat belts receive a warning.
Play It Safe
The best way to enjoy driving in Japan is to drive carefully, drive responsibly, and wear your seat belt at all times. Make sure all your passengers are wearing theirs, and you will have no problems with Japan's seat belt regulations.