The Government has confirmed coronavirus passports will be available "as soon as possible" and Spain declared itself "desperate to welcome" UK visitors.
Many popular tourist destinations will require international visitors to have been vaccinated or recently tested before they can enter.
The development of a coronavirus passport, also known as a health certificate, will enable UK holidaymakers to meet that obligation.
Foreign holidays could be permitted for people living in England from May 17 under Prime Minister Boris Johnson's road map for easing pandemic restrictions.
A Department for Transport spokeswoman said: "We are working on a solution to enable residents to prove their Covid-19 status, including vaccination status, to other countries on the outbound leg.
"We are working on this as a priority and intend to have the solution ready as soon as possible."
The Daily Telegraph reported that a Government official told travel industry leaders in the Tourism Industry Emergency Response Group: "We aim to give people the ability to prove their vaccine status by the time international travel restarts where other countries require it."
Coronavirus passports, also known as health certificates, would initially only be available for people travelling abroad, and a wider scheme for domestic use is unlikely to be ready by next month, according to the newspaper.
Spain's tourism minister said the country is "desperate to welcome" UK visitors this summer.
Fernando Valdes told Sky News: "I think we will be ready here in Spain. We also think that the vaccination scheme in the UK is going pretty well, so hopefully we'll be seeing this summer the restart of holidays."
He added that certificates enabling holidaymakers to prove they have been vaccinated or recently tested are "going to help us".
Mr Valdes insisted Spain is "pushing hard" to persuade the European Commission to reach agreements to reopen travel between "third parties such as the UK" as well as EU member states.
"If we reach these kind of agreements from the month of June, we will be able to have a summer," he said.
"Probably not as the one we had in 2019, but obviously the restart of tourism again."
But the Transport Select Committee warned that the resumption of international travel is in jeopardy with "vague and costly" proposals not enough to reboot the aviation and tourism sectors.
It said a report produced by the Government's Global Travel Taskforce gave "insufficient" detail to allow businesses and travellers to prepare for holidays to safely resume on May 17.
It added that testing requirements could be "disproportionate to the risk" and may add £500 to the cost of a family of four visiting the "safest" parts of the globe where vaccine rollout is comparable to the UK.
Huw Merriman, who chairs the committee, said: "The aviation and travel sectors were crying out for a functional report, setting out clear rules and offering certainty. This is not it."
