Riot police at Greece’s largest port cordoned off an area around an Israeli cruise ship that arrived early on Thursday to prevent several hundred protesters from approaching the vessel.
Protests have been held at Greek islands and mainland ports along the route of the Crown Iris, several of which have led to clashes with police.
At the port of Piraeus near Athens demonstrators held flares and waved Palestinian flags behind a cordon formed with riot police buses.
Protest organisers, citing online posts from travellers, said off-duty Israeli soldiers were among the passengers.
"They are unwanted here and have no business being here," protest organiser Markos Bekris said. "The blood of innocent people is on their hands and we should not welcome them."
Greece is a popular holiday destination for Israelis. But the ongoing Israel-Hamas war in Gaza and global attention about the widespread destruction and severe food shortages have triggered hundreds of anti-Israel protests in Athens and other Greek cities, as well as a political confrontation.
Left-wing opposition parties are calling on the conservative government to halt commercial and broad military cooperation with Israel.
Demonstrations against Israel's military offensive in Gaza erupted in the city of Volos on Wednesday after the Crown Iris docked there.
Local communities unfurled huge Palestinian flags and chanted pro-Palestine slogans as Israeli tourists disembarked from the cruise ship.
Last month, the Crown Iris left the Greek island of Syros early without its passengers disembarking after more than 150 protesters demonstrated at the island's port.
There have been similar protests at other stops on the Crown Iris’ route such as in Rhodes and Crete.
However, not all Greeks are on board with the demonstrations, including the country's Health Minister Adonis Georgiadis.
"We owe an apology to these friends of Greece who chose to spend their holidays here and were forcibly denied it by some," he wrote on X last month following the incident in Syros.
"Our country remains hospitable to all and antisemitism has no place here!"
