Portugal and Hungary are being added to England and Northern Ireland’s quarantine list, meaning any travellers arriving from 4am on Saturday will have to isolate for two weeks.
The restriction will not apply to travellers returning from Portuguese island Madeira and the Azores.
French Polynesia and Reunion have also been added to the list of countries from which travellers to England and Northern Ireland will have to quarantine for 14 days, which will also be enforced from early Saturday morning.
Live coverage of the latest coronavirus news and updates
However, those arriving in England and Northern Ireland from Sweden from Saturday morning will no longer need to isolate after a so-called “travel corridor” was established.
Transport Secretary Grant Shapps announced the latest changes to England’s quarantine measures as he hailed how “enhanced data” meant the government now has “the capability to assess islands separate to their mainland countries”.
He also reminded all travellers to the UK they must complete a Passenger Locator Form prior to entry.
“This is vital in protecting public health and ensuring those who need to are complying with self-isolation rules,” he posted on Twitter.
“It is a criminal offence not to complete the form and spot checks will be taking place.”
The Portuguese foreign ministry has said it “regrets” the decision to remove its mainland from its safe travel list.
Wales and Scotland have also made changes to their travel lists, both removing Hungary and Reunion as safe destinations for travellers, requiring arrivals from those places to quarantine from 4am on Saturday.
Wales and Scotland also now deem Sweden a safe place to travel to.
It comes a week after England made no changes to the travel corridors – but Wales and Scotland both took different approaches, sparking anger and confusion from some holidaymakers.
Sky News reporter Annie Green is in the Algarve, on Portugal’s south coast, and said many British holidaymakers were expecting the decision to be made this week.
However, some described it as “ridiculous”.
“We can work from home” one couple told Sky News. “But it’s our daughter who now can’t go to college which is the biggest issue”.
Another couple said they felt lucky as, unlike others, they are able to work from home.
Last Thursday, Wales added Portugal to its quarantine list – but excluded the Azores and Madeira – while Scotland took a blanket approach to the whole country.
Some tourists had been expecting England to do the same, cutting short holidays and forking out hundreds of pounds for early flights home, given the coronavirus infection rate was as high as 23 per 100,000 people.
:: Subscribe to the All Out Politics podcast on Apple Podcasts, Google Podcasts, Spotify, Spreaker
Ministers say countries where the figure is higher than 20 per 100,000 are at risk of being added to the list – but at the start of this week the UK tipped over that threshold itself.
The biggest restrictions since the first COVID-19 lockdown have been announced in response, significantly cutting the maximum number of people able to gather legally.
Changes have been made to England’s quarantine system too, so now islands can be treated separately from whole countries.
Mr Shapps made the announcement on Monday, and at the same time added seven Greek islands popular with sun-seeking Britons to the quarantine list.