Abu Dhabi has removed the UK from its green list of travel destinations.
The decision means unvaccinated passengers from the UK must quarantine in a residence or hotel for 10 days on arrival in Abu Dhabi.
Vaccinated passengers from non-green list countries are tested on arrival and six days later. They are not required to quarantine.
The test-on-arrival at Abu Dhabi airport is free, and the day six test is free in any clinic run by the public hospital group Seha.
The updated list, which is effective from Monday, January 3, comes after a surge in Covid-19 cases in many countries, largely tied to the Omicron variant.
Dubai has separate rules, including testing on arrival from some destinations. It requires only people who test positive to quarantine.
On Saturday, the UAE government said it will ban unvaccinated Emiratis from travelling abroad from January 10. The decision was not extended to expats.
Live updates: follow the latest news on Covid-19 variant Omicron
Updated Abu Dhabi green list includes:
Bosnia and Herzegovina
Hong Kong (SAR)
Papua New Guinea
Republic of Ireland
Taiwan, Province of China
United States of America