ATHENS — Plans to reopen to tourists in the spring busted for now as COVID-19 cases kept rising, Greece's New Democracy government will take another shot for entry on May 15 for most countries after allowing those from Israel and a few select countries for now.

April, when the weather turns warmer and flowers bloom, has been the annual gateway date for an introduction to the summer high season but tourism-dependent areas are still mostly empty, including popular islands like Santorini.

Greece said it would allow visitors who can show proof of full vaccination or negative tests, who wouldn't have to face tests or quarantines, and there are hopes that the United States' fast-moving vaccine plan will allow Americans, a critical market.

In a feature, the BBC noted the air of uncertainty mingling with the scent of honeysuckle and jasmine as trees bud, this year even more pleasant, and as the New Democracy government has for now eased a lockdown to allow most retailers to open, with conditions.

Eugene Theodoridis, who, with his team, rents out catamarans and yachts for trips to the Greek islands, catering to clients from the United Kingdom, the US, Germany and South Africa are looking at the summer horizon.

"All through the winter, we have been preparing the boats in order for the tourists to come," he told the BBC. "We will be ready when the borders open and we can welcome all guests throughout the world."

"You understand that this does not depend solely on us," he said. "A lot of nations need to agree on specific protocols in order to allow people to travel,” he said, Greece relying on tourism to bring in a much as one-fifth of its Gross Domestic Product (GDP) of 170.54 billion euros ($200.3 billion) and the biggest employer.

Culture Minister Lina Mendoni said she believes the vaccination certificates are very important to make "everybody will feel really safe,” the country already allowing open-air archaeological sites to open.

Greece’s plan to open to tourism May 15 – with conditions during the COVID-19 pandemic – saw British Airways jockeying for position to use bigger jets on shorter routes to popular areas in the country.

That would put the airline, the industry brought to a near standstill by the pandemic, in a spot to gain more revenues as others scramble to fly to Greece, expected to be a world favorite for travelers this year.

The United Kingdom and Greece have ramped up vaccination campaigns and Greece said tourists with proof of being inoculated or showing a negative COVID-19 test would be welcome.

The New Democracy government is eager to kick start tourism, the country’s biggest revenue engine, to bolster a staggering economy, the sector having been on a run of consecutive record years before COVID-19 struck.

British Airways sources not named told the financial news agency Bloomberg the airline – UK tourists are a big market in Greece – will use some of its biggest airplanes to carry more people into the country for summer vacations.

Greece still hasn’t said whether visitors would be allowed from the key market of the United States and its vast Greek-American diaspora who were shut out of coming in 2020 when the pandemic kept them away.

The government hopes tourism will bring in 11 billion euros ($12.92 billion) this year the report said, more than twice the 4.5 billion euros ($5.29 billion) in takings in a disastrous 2020 pandemic shutdown.

Several consecutive years of record runs before the pandemic had seen some 30 million visitors bringing in more than 35 billion euros ($41.11 billion) as the country’s biggest revenue provider.