The rules on testing are to be eased for people travelling to England, the government announced following calls from the travel industry.
From 04:00 GMT on Friday, fully vaccinated travellers coming to England will no longer have to take a test before they travel.
And from Sunday, rather than taking a PCR test on day two of arrival, they can take a cheaper lateral flow.
The rules for self-isolating on arrival will also change.
The shake-up was confirmed by Boris Johnson earlier, following calls from travel firms who said the measures were not effective now that Omicron was spreading widely.
Prime Minister Boris Johnson said the pre-departure test “discourages many from travelling for fear of being trapped overseas and incurring significant extra expense”.
The announcement comes after airlines said passenger testing was making no real impact, with data last week suggesting one in 25 people in England had the virus.
They also said compulsory testing had held back the sector’s recovery.
Mr Johnson met his cabinet earlier and alongside changes to travel tests, the government has said it will ease Covid testing rules for people without symptoms, who will no longer need to confirm a positive lateral flow test with a PCR.
On Tuesday, Mr Johnson said he hoped the country could “ride out” the current wave, although he acknowledged parts of the NHS would feel temporarily overwhelmed.
That rule change will come into force on 11 January and apply to England only for now.
Following the announcement for England, Health Minister for the Welsh government Eluned Morgan said: “I have today reluctantly agreed to remove the requirements for fully vaccinated travellers and under 18s to take a pre departure test (PDT) and a day 2 PCR test when arriving in the UK.”