Mykonos has welcome 186 enforcers, an increase of 130 from last year when tourism was scarce.
And Ios, another tourist hotspot, saw another 30 police officers arrive with undercover agents and security officials.
Both islands are now under “orange” alert on Greece’s risk-assessment system.
Concerns have also ramped up for six other islands, including Tinos, Zakynthos, Santorini, Rhodes, Paros and Lefkada.
