Holidaymakers are now required to wear masks in indoor public spaces such as shops, food stores, and other municipal buildings, or face a €150 (£135) fine.
Masks are already mandatory in Greece when travelling by all forms of public transport, and in several other scenarios.
The move was confirmed by Greece’s deputy minister for civil protection and crisis management, Nikos Hardalias, earlier this week, who said the country and any visitors "are going to have to learn to live with the use of masks".
The Foreign Office has updated its travel advice to reflect the new rules on mask wearing.
"Face masks are also obligatory in indoor spaces, including medical facilities, lifts and any enclosed venue providing goods or services, including supermarkets, grocery stores, bakeries, cafes, banks, government and utility providers’ offices, retail shops, barber shops, hairdressers and beauty parlours."
