ATHENS – Optimism is growing for a relative boom summer tourism season in Greece – far off the mark from previous record years – but with more travelers on the way, said Prime Minister Kyriakos Mitsotakis.

The door was opened on May 14 to tourists who are fully vaccinated, had negative molecular tests, had recovered from the Coronavirus and required to fill out a Passenger Locator Form about their travel countries and plans.

“I am cautiously optimistic that the second half will be better than we have expected and that we eventually achieve the target of 50 percent of 2019 revenues,” Mitsotakis told the general assembly of Greece’s tourism confederation SETE, said the Reuters news agency.

Greece said it would also launch a COVID-19 certificate before the European Union does on July 1, a belated attempt to lure tourists after the bloc's leaders sat on their hands for the plan, which was his idea.

While Americans are welcome, the United Kingdom still hasn't lifted a requirement that travelers would have to quarantine on return, a near-prohibitive condition that would see Greece lose that key market unless it's lifted.

Greece gets as much as 18-20 percent of its revenues annually from tourism, but after 33 million people came in 2019 only seven million arrived in 2020 as the pandemic was raging across the world.