For the protection of passengers and citizens from COVID-19, the following restrictions apply until 6:00 a.m., October 29th 2021:
The residents of European Union & Schengen Area countries, the USA, the UK, Serbia, Australia, New Zealand, South Korea, Singapore, the United Arab Emirates, the Russian Federation, Israel, Canada, North Macedonia, Ukraine, China, Saudi Arabia, Qatar, Kuwait, Belarus, Bahrain, Bosnia-Herzegovina, Montenegro, Albania, Japan, Lebanon, Azerbaijan, Armenia, Jordan, Moldova, Brunei, San Marino, Andorra, Vatican City, Monaco, Turkey, Kosovo, and Chinese Taipei may visit Greece for pleasure.
All flight passengers must fill in the Passenger Locator Form (PLF) at any time before their flight departure for Greece.
Upon arrival, the residents of the above countries will have to show:
See complete info here