Seven EU countries have introduced a vaccination certificate system for travellers, weeks ahead of the July 1 roll-out of the program across the 27-member bloc, as the UK registered no daily coronavirus-linked deaths for the first time since March 2020.
Germany, Bulgaria, the Czech Republic, Denmark, Croatia, Poland and Greece were the countries starting early, according to the European Commission.
Greece, which depends heavily on tourism, has been pressing for the commonly-recognised certificate that uses a QR code with advanced security features.
The certificates are being issued to people who are fully vaccinated as well as those who have already contracted the virus and developed antibodies and others who have had a PCR test within the last 72 hours.
The documents will have both digital and paper forms.
They'll be free of charge, distributed in the national language plus English and be valid in all the bloc's countries.
"EU citizens are looking forward to travelling again, and they want to do so safely. Having an EU certificate is a crucial step on the way," EU Health Commissioner Stella Kyriakides said.
Greece's digital governance minister, Kyriakos Pierrakakis, said easier travel will open up within the EU as countries adopt the new verification standard.
"What will happen is that countries will stop issuing certificates using their own convention and adopt the common convention. That will simplify things considerably because you can imagine the number of bilateral agreements that would otherwise need to be worked out," Pierrakakis told private Skai television.
Kyriakides said in the next few weeks, all EU countries need to "fully finalise their national systems to issue, store and verify certificates, so the system is functioning in time for the holiday season."
Countries will be allowed to add extra vaccines to their individual entry list, including those that have not been formally approved for use across the EU.
The EU Commission believes that people who are vaccinated should no longer have to be tested or put into quarantines, regardless of where they are travelling to or from, starting 14 days after receiving their second shot.
Member countries, however, have not yet endorsed that recommendation.
Meanwhile, the UK has recorded no new deaths within 28 days of a positive COVID-19 test on Tuesday.
The last time the UK recorded no deaths was in March 2020, before the country had entered its first lockdown.
The figure on Tuesday relates to how many deaths have been reported and it comes after a holiday on Monday - a factor which has in the past skewed the data.
The UK's overall death toll from the pandemic stands at 127,782 and is the fifth highest in the world according to John Hopkins University data.
UK government data showed 3165 new cases of the virus, broadly flat on the previous day.