According to the official website of the Hellenic Ministry of Culture and Sports:

Admission to archaeological sites, historical sites, monuments and museums owned by the State and managed by the Hellenic Ministry of Culture and Sports is free of charge for all visitors (without fee payment), on the following dates:

• March 6th (in memory of Melina Mercouri)
• April 18th (International Monuments Day)
• May 18th (International Museums Day)
• The last weekend of September annually (European Heritage Days)
• October 28th (National Holiday)
• Every first Sunday of each month from November 1st until March 31st.

The free admission tickets for these dates are exclusively issued at the ticket offices, while you can generally book your tickets for more than 25 Museums, Monuments & Archaeological Sites in Greece on https://hhticket.gr.

Additionally, please note that there is increased attendance and the availability is limited.
If you want to secure your free entry to the country’s top museums and monuments, such as the Acropolis and its museum, you can book a tour of our travel agency here.

Mark your calendar for these entrance fee–free dates and embark on a journey through Greece’s captivating history and cultural marvels.