Portugal's smokers were counting down the hours Monday to the country's tentative joining of Europe's anti-smoking wave, effective on January 1.
A law restricting smoking rights in public buildings, and licensed premises under 100 square metres in size (1,076 square feet), comes into force at midnight on Monday after it was passed, with considerable amendments, by the Portuguese parliament in June.
Like in neighbouring Spain, the licensed premises can choose whether to remain smoking, or become non-smoking.
Other buildings for public use, from workplaces through shopping centres to schools, can still allow for smoking rooms, provided they are "clearly marked and ventilated."
Fines of between 50 euros (70 dollars) and 750 euros await individuals who break the ban, with licensees and other building owners facing sums between 50 and 1,000 euros.
The age at which smokers will be able to buy cigarettes is also raised to 18.