The passengers arrived on a Qatar Airways flight.
“Following these epidemiological facts, flights from and to Qatar are suspended until June 15,” the Greek Civil Protection Authority said in a statement.
Greek officials said those testing positive for COVID-19 included nine Pakistani nationals who are legal residents of Greece, two Greeks from Australia and a member of a Greek-Japanese family.
Officials added that the passengers who tested positive will be quarantined in a hotel for two weeks. The rest, who did not test positive, will be quarantined and monitored for one week.