Canada, Denmark, Finland and Switzerland are among the latest nations to be added to the green travel list.
The Department for Transport has revealed its latest changes to the COVID-19 travel rules, with all of the alterations taking effect from 4am on Monday.
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Lithuania, Lichtenstein and The Azores have also been added to the green list.
Meanwhile, Thailand and Montenegro have been added to the red list, meaning anyone returning from those destinations will have to pay more than £2,000 to isolate for 11 days in a quarantine hotel.
Identical changes have been announced by the devolved administrations in Scotland and Northern Ireland, but Wales has not yet confirmed if it will make the same move.
For countries on the green list, people do not have to quarantine when returning from these nations, regardless of their vaccination status, although they have to take a pre-departure test before flying home and another two days after arrival.
Meanwhile, fully-vaccinated travellers who received their jabs in the UK, EU and US are able to travel to amber list nations and do not have to quarantine upon their return, along with those under the age of 18.
Transport Secretary Grant Shapps said: “We’ve updated our travel lists further cautiously easing international travel.”
A spokesman for Airlines UK, the industry body that represents UK-registered carriers, said the “small number of green destinations” is making international travel “more expensive, burdensome and uncertain compared to our neighbours”.
He added: “Too many families are having to look over their shoulders for rule changes and pay through the nose for tests, with no sign from government that this will change.
“As has already happened across Europe, it’s time for a more proportionate system where tests are dropped for the fully-vaccinated and from destinations where COVID risks are low, with tougher measures targeted at a small number of high risk countries.”
Meanwhile, Labour’s shadow transport secretary Jim McMahon warned that “any loosening of restrictions carries with it risks, particularly from variants that could undermine the progress we have made on vaccines”.
Turkey remains on the red list, despite the country’s embassy in London telling Sky News earlier this week that it expected the nation to be moved to amber.
Similarly, Pakistan is still on the red list.
The country’s top diplomat in the UK said earlier this month that Boris Johnson assured him the government was “looking into” the prospect of removing Pakistan from the red list.