Prime Minister Boris Johnson said earlier on Wednesday that he wants American citizens to be able to come to Britain “freely” as they did before the pandemic.
Fully vaccinated travellers from the EU and the US will not have to quarantine when arriving in England, Scotland and Wales from an amber list country.
Transport Secretary Grant Shapps said the change regarding US and EU arrivals will come into force from 4am on 2 August.
Applicable passengers must have received two jabs with vaccines authorised by the European Medicines Agency (EMA), or in the US with vaccines authorised by the Food and Drug Administration (FDA).
They will still be required to complete a pre-departure test before arriving in England, Scotland and Wales, alongside a PCR test on or before day two after they have landed.