A law banning indoor smoking in principle took full effect across the nation on Wednesday as part of an effort to protect people from passive smoking going into the Tokyo Olympic and Paralympic Games.
The revised health promotion law bans smoking at restaurants, hotels and offices, with offenders facing penalties.
The law partially went into effect last year, banning smoking at schools, hospitals and government offices.
Eating and drinking are not allowed in smoking rooms and people aged under 20 are not allowed to enter the rooms.
Separately, a Tokyo Metropolitan Government ordinance fully took effect on Wednesday banning smoking in principle at all restaurants employing workers.