Transport Secretary Grant Shapps said the UAE has been added to the government's "red list" along with Burundi and Rwanda from 1.00pm (1300GMT) on Friday.
Any British or Irish citizens and third country nationals with residence rights returning from the Gulf state will be required to isolate at home, or in a hotel for 10 days.
Everyone else is banned completely, and the government also announced that direct flights between Britain and the UAE were no longer allowed.
"The decision to ban travel from these destinations follows the discovery of a new coronavirus variant first identified in South Africa, that may have spread to other countries, including the United Arab Emirates, Burundi and Rwanda," said a government spokeswoman.
Read also: The geopolitics of vaccine diplomacy in the Middle East
The state is home to thousands of British expats and has been a popular destination for social media influencers during the pandemic, who have raised ire by posting their holiday pictures online having travelled under the guise of work.
Dubai last week clamped down on its entertainment scene and suspended non-essential surgery in hospitals after a spike in coronavirus cases.
One of the seven emirates that make up the UAE, Dubai has branded itself this winter as an open, sunny and quarantine-free escape.
But Covid-19 infections have surged since the New Year.
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