Thailand and Montenegro are being added to the government’s red travel list, while the Azores, Switzerland, Denmark and Canada are among seven locations being moved to the green list, the Department for Transport said.
It means people returning to the UK from “red” destinations will be forced to enter a quarantine hotel.
Popular European holiday destinations including Spain, France and Greece have remained on the amber list, which means returning travellers who are not fully vaccinated must self-isolate at home for 10 days, take one pre-departure test and two post-arrival test.
All arrivals from green list locations must take a pre-departure test and another after they land.
Those travelling from an amber country must take the same tests, plus a second post-arrival test.
The changes will be implemented from 4am on Monday.
The Azores are a Portuguese archipelago in the mid-Atlantic.
Travel lists, which determine the quarantine and testing requirements for people arriving in the UK, are updated every three weeks.
Fully vaccinated travellers are exempt from quarantine, but must still take one pre-departure test and one post-arrival test.
Sean Doyle, British Airways’ chief executive, said: “Despite our world-leading vaccination programme, the UK’s economic recovery remains far behind our more pragmatic European neighbours, which are already reaping the rewards of a rapid recovery.
“It cannot be right that although 77% of us have been fully vaccinated we have a much more costly, prohibitive and restrictive testing regime than everyone else, when data suggests just four out of every 1,000 travellers tests positive for coronavirus on their return to the UK, less than the overall rate at home.
“These stats strongly suggest PCR tests should only be needed following a positive lateral flow test.
“We also need to urgently end the uncertainty caused by the constant threat of changes to countries’ traffic light status. Our green list is much smaller than that of the US and EU, despite no new variants being transported into the UK.”
A spokesman for Airlines UK, the industry body representing UK-registered carriers, said the “small number of green destinations” is making international travel from the UK “more expensive, burdensome and uncertain compared to our neighbours”.
He went on: “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.”
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”.