Ibiza, Mallorca and Menorca will be added to the amber travel list due to a surge in coronavirus cases, a little over a fortnight after they went green.
The change for those returning to England from Spain’s Balearic Islands will take place at 4am of Monday, potentially sparking a rush for holidaymakers to return to avoid the need to quarantine.
Younger adults will mainly be impacted because the alteration coincides with the end of the need to quarantine for fully-vaccinated UK residents and under 18s when returning from amber list nations.
Meanwhile, Bulgaria and Hong Kong will be added to the green list – meaning there is no requirement to isolate on return for any travellers regardless of the vaccination status.
Croatia and Taiwan will be added to the “green watchlist”, meaning there is no need for anyone to quarantine but they are at risk of going amber.
The British Virgin Islands will also go amber, while Cuba, Indonesia, Myanmar and Sierra Leone will be added to the red list requiring 10 days of isolation in a quarantine hotel.
Transport Secretary Grant Shapps said measures for the Balearics were being upgraded due to case rates having doubled since they were added to the green list on June 30.
Mr Shapps told reporters: “Surely no one can be out there thinking we can travel and just rely on things not changing.
“When we see things change for the safety and security of everyone back home we do need to react and act, and that’s what we’re doing today.”
The changes to the Balearics will mainly affect younger adults because they are far less likely to have received both jabs and therefore will not benefit from the incoming exemption.
Virginia Messina, a senior vice president at the World Travel and Tourism Council industry body, said: “This will throw summer holidays into disarray for tens of thousands of people.
“Businesses given the lifeline of holidays to the Balearics will also be left floundering as bookings collapse and customers clamour for refunds, piling on further financial pressure.
“There may be some good news with Croatia and Bulgaria moving up the scale and being added to the green list. But the overall impact is one of confusion, which will only deter more Brits from holidaying abroad as the summer season slips away.”
Ministers decided the changes to the travel lists on Wednesday after receiving analysis from the Joint Biosecurity Centre.
Even the green list does not mean travel as normal, with a pre-departure test being required as well as another two days after returning back in England even from green nations.
Health agency figures showed two-thirds of adults in the UK are estimated to have received both doses of a Covid-19 vaccine.
But the Government also reported the highest daily rise in coronavirus cases since January 15 when an extra 42,302 lab-confirmed Covid-19 cases in the UK were announced.
A further 49 people had died within 28 days of testing positive for Covid-19 as of Wednesday, bringing the official total to 128,530.