Travellers from mainland Portugal to England will have to quarantine from 04:00 on Saturday, just weeks after the country was previously declared exempt.
Wales and Scotland had already imposed the mandatory two weeks of self-isolation from 4 and 5 September.
Quarantine-free travel is still allowed from the Portuguese islands, the Azores and Madeira.
Sweden has been added to the list of countries exempt from quarantine requirements.
People travelling to England and Wales from Hungary, French Polynesia and Reunion will also be required to self-isolate.