Non-essential travel will no longer be classed as illegal from May 17, but strict border control measures will be in place for those entering the UK in order to keep a check on coronavirus variants.
India remains on the "red list" since last month amid a second wave surge in coronavirus infections, which means all travel remains banned between India and the UK except for British residents and nationals who must self-isolate for 10 days in a designated quarantine hotel.
The Maldives, Nepal and Turkey have now been added to the "red list" of around 40 countries, amid concerns around new variants.
At a Downing Street press conference on Friday, UK Transport Secretary Grant Shapps announced an end to the "Stay in the UK" rules from later this month, with the green list territories open for easier travel including Portugal, Australia, New Zealand, Singapore, Brunei, Iceland, Faroe Islands, Gibraltar, Falkland Islands, and Israel and Jerusalem.
"Today marks the first step in our cautious return to international travel, with measures designed above all else to protect public health and ensure we don''t throw away the hard-fought gains we''ve all strived to earn this year," said Shapps.
"This is a new way of doing things, and people should expect travel to be different this summer – with longer checks at the borders, as part of tough measures to prevent new strains of the virus entering the country and putting our fantastic vaccine rollout at risk," he said.
The government warned that many "green list" countries will continue to place restrictions on UK travellers, including quarantine measures, so passengers must check the Foreign, Commonwealth and Development Office (FCDO) advisory before booking any holidays or journeys.
Countries have been allocated according to the latest scientific data, so quarantine and testing requirements on return from those countries are appropriate to the risk of coronavirus and variants of concern, the Department for Transport (DfT) said.
The lists will be reviewed every three weeks, informed by public health advice, including the Joint Biosecurity Centre''s assessment of the latest data.
These regular review points will allow the government to balance helping the public to understand COVID-19 requirements when travelling to England while allowing constant evaluation of the risk for different countries.
The government will also be publishing a green watchlist in the future, to provide an indication when a country is identified as a candidate for a changing country, in an effort to help the public with holiday planning.
Countries will decide whether they require proof of COVID-19 vaccination for entry, and it will be the traveller’s responsibility to check individual requirements.
If needed, people in England who have both vaccine doses will be able to demonstrate their COVID-19 vaccination status via the National Health Service (NHS) application from May 17.
Those without access to the application can request a letter from the NHS proving their vaccination status by calling 119.
The UK government is working with the devolved administrations to ensure this facility is available to everyone across the UK.
Passengers from any destination will still be required to fill out a Passenger Locator Form (PLF), and show proof of a pre-departure negative coronavirus test result.
"While holidaymakers may notice longer than usual queues, it is vital we maintain our stringent border checks – which are among the toughest in the world – to prevent new strains of the virus entering the country and putting our vaccine roll out at risk," DfT said.
UK Border Force officers will be checking that arriving passengers have complied with current health measures.
Airlines will be required to carry out all necessary checks or risk facing fines of GBP 2,000 for each passenger they carry who does not have a valid pre-departure test certificate, and GBP 2,000 for each passenger who does not have a completed PLF.
The coronavirus has killed 127,858 people in the UK so far, along with over 4.4 million confirmed cases, according to Johns Hopkins University.