New simplified travel rules have come into force in the UK, with the traffic light system replaced by a single red list.
Most fully vaccinated travellers arriving from non-red list countries will no longer have to take a test before setting off for the UK.
Airlines UK said it would make travelling abroad easier and cheaper.
But those coming from red list destinations must still pay to quarantine in a hotel for 10 days.
New simplified travel rules have come into force in the UK, with the traffic light system replaced by a single red list.
Under the changes, which came into force at 04:00 BST, the green and amber lists have been scrapped.
Testing rules are also being eased for people travelling from non-red list destinations who have been vaccinated in the UK, the EU, the US, or any of 18 other recognised countries.
Anyone under 18 who is resident in those countries can also travel to the UK without testing.
These groups were already able to avoid self-isolating on their arrival back in the UK.
All travellers – except children under five years old – will still have to pay for a PCR test two days after arrival.
People who are not fully vaccinated will need a pre-departure test and a PCR test on days two and eight after they return, and must self-isolate for 10 days at home.
And those arriving from red list countries, including Brazil, Mexico, the Philippines and South Africa, must quarantine for 10 days in a government-approved hotel, at a cost of £2,285 for one adult. Only UK or Irish nationals, or UK residents, are allowed to enter the UK if they have been in a red country in the previous 10 days.
The red list is due to be updated later this week.
The government may also announce additions to the list of countries whose vaccination certificates are recognised by the UK.
Transport Secretary Grant Shapps said: “We are accelerating towards a future where travel continues to reopen safely and remains open for good, and today’s rule changes are good news for families, businesses and the travel sector.
“Our priority remains to protect public health but, with more than eight in 10 people now fully vaccinated, we are able to take these steps to lower the cost of testing and help the sector to continue in its recovery.”
There was a surge in holiday bookings after the government announced the changes last month and the travel sector has welcomed the move.
The industry previously criticised the government for being too slow to ease and simplify rules on testing and quarantine.
From later in October, the government has said fully vaccinated people coming to England will no longer have to take a PCR test two days after arrival and can take a cheaper lateral flow test instead.
No date has been set for this change but ministers are aiming to have it in place for the half-term school break.
So far, no other UK nation has followed suit.
Scotland has said it will “align with the UK post-arrival testing regime” but has not announced further details. The Welsh government said it had “concerns” about easing its testing regime.
Tim Alderslade, chief executive of Airlines UK, which represents UK carriers, said: “Things are moving in the right direction and the removal of these restrictions will make it easier and cheaper for people to travel.”
However, he said the UK remained “an outlier on arrivals testing for vaccinated passengers”.
Airlines UK hopes to see more countries removed from the red list at the next update and further mutual recognition of vaccine status for those jabbed in other countries, he added.
Willie Walsh, head of industry body the International Air Transport Association, welcomed the change as a “positive step”, saying the government’s testing and quarantine restrictions had been both unscientific and costly.
“People have been led to believe that the risk is people flying into the country. The risk was inside the country,” he said.
Alan French, chief executive at Thomas Cook, said more options would now be available for travellers.
“They will be more confident if they book the holiday, they can travel safely there and be able to return in a transparent way, which is something they’ve not been able to do,” he said.
Mr French said since the government announced the changes, three weeks ago, his company had seen bookings more than double.
The UK recorded 30,439 cases on Sunday, with the total number of cases in the past seven days up one per cent on the previous week.
However, the number of Covid deaths and hospital admissions are falling, with 43 deaths within 28 days of a positive test reported on Sunday.