According to Government Gazette 2661/18.06.2021 (Article four) the following applies for the entry of truck drivers into Greece from Saturday, 19th of June 2021 at 06:00 until further notice:
Trucks drivers, regardless of nationality, performing freight transportation on the Italy-Greece routes (to the ports of Patras, Igoumenitsa and Corfu) must submit at departure port a COVID-19 self-test declaration of negative result before boarding the ship, as well as the PLF electronic form at www.travel.gov.gr
Upon arrival at the Greek port of destination, drivers are required to present to the competent Greek authorities the above self-test declaration and are subject to mandatory examination for rapid detection of coronavirus COVID-19 antigen (rapid test).
You will also find attached the self-test result declaration form.
Truck drivers are advised to arrive at the port of departure on time in order to facilitate the pre-boarding inspection process.