The FCDO further warns: “You should also be aware that if other passengers on your flight, bus, train or ferry later test positive, you may be subject to further quarantine/self-isolation requirements.
“These will be mandatory and you should comply with the Greek authorities’ requirements.”
In addition, arrivals into Greece may be asked to undertake a rapid COVID-19 test on arrival.
“If you test positive on arrival in Greece, you (and those you are travelling with) will have to self-isolate in quarantine hotels provided by the Greek state for at least 10 days,” the FCDO’s travel advice explains.
source: express.co.uk