Travellers have been warned to check their half-term holiday plans to make sure they meet Covid vaccination rules when travelling to EU destinations as a growing number of countries impose new restrictions.

France joined Spain and Denmark last week in requiring anyone who completed their vaccination jabs more than 270 days ago to have a booster to enter the country – or be considered unvaccinated. Austria requires boosters after 180 days.

It means that any of the 18 million people in the UK who had their second dose before mid-May in 2021 would need to have been boosted if they travel to those countries on Saturday, 12 February. Yet only 65% of over-12s have had a booster so far.

People travelling to Italy, Croatia and Switzerland, as well as New York or California, will not face the same border checks but may find it harder to go to restaurants, museums and other indoor venues if they have not been boosted.

Tourism leaders urged ministers to negotiate with European countries to prevent chaotic scenes at airports as the travel industry begins to revive.

“It is too late now for regulations to change [before half term],” said Chris Rowles, the chair of Aito, which represents specialist travel companies. “Travellers, especially with children under 18, will have to be careful and well aware of individual countries’ regulations to ensure they can travel without problems.”

The EU had been trying to develop a common approach between the 27 member states, he said, but they had taken different approaches.

“What our government must do is negotiate with the EU to ensure that we are included in any joint EU regulations to make travel more seamless across Europe,” Rowles said, adding that the rules should be agreed for all four nations in the UK.

Craig Burton, managing director of Ski Solutions, said most skiers had been aware of the issues, but the different restrictions had made things “really complicated”, particularly for families with children under 12, most of whom cannot be vaccinated in the UK, but face vaccine requirements in some countries.

“We have heard of some people getting caught out by the passport validity rules, when they’re dusting down their passport for the first time in a couple of years,” Burton said. EU rules require travellers from third countries such as the UK to have a passport issued within the last 10 years – some British passports include extra months if they were renewed early.

Rules within countries sounded “scary”, Burton added, “but it’s manageable”. “I was in Italy last week. They have the ‘super green pass’ [to prove vaccination status]. You download the QR code from your NHS app and save it as a screensaver, show it at the ski lifts and away you go.”

Paul Charles, chief executive of travel consultancy the PC Agency, said: “Overall, it’s clear that we’re in a no-man’s-land phase coming out of the pandemic. It’s causing a lot of confusion because people are having to do calculations about when they’ve had the vaccine, and, if they’ve got children, whether they’ve had enough vaccines.

“We’re seeing a jigsaw puzzle of restrictions emerging, and customers will choose somewhere that’s easier to go. This is a key booking period for the summer holidays, and France is going to lose out enormously.”

Tom Jenkins, the chief executive of ETOA, the trade association for tour operators in European destinations, said most travellers would not be surprised to have to navigate complex restrictions. “What people probably aren’t prepared for is the scrutiny that British passport holders are going to be subjected to once they arrive in Europe,” he said.

“This has been a phenomenon at the margins of most travellers’ awareness. Now they’re going to find themselves in the midst of it. We’re used to seeing non-EU travellers standing in a queue to get into Paris or Italy. Now British nationals will be part of that queue.”

Since the UK formally left the EU on 1 January 2021, British travellers have faced passport checks. With traveller numbers depressed by the pandemic, that has not made much difference to the experience of many people so far. But as the volume of British tourists increases, they will test the capacity of officials in some destinations to process non-EU travellers.

The appetite for foreign holidays appears to be returning. Tui said it was seeing strong demand for the Canaries, Greece and mainland Spain.