If your outing or business trip schedule requires it, you may stay overnight before or after with your supervisor's permission.
The rule of thumb for staying overnight before is when the departure time from home is earlier than 7:00 a.m., and the rule of thumb for staying overnight after is when the return time from home is later than 10:00 p.m. However, supervisors should make their decision from the perspective of employee safety and productivity, taking into consideration individual circumstances such as the time and number of the first and last train departures.
Please refer to People Connect's “Rules and Regulations for Going Out of the Office and Business Trips in Japan” for other considerations regarding outings and business trips.