From Monday, unvaccinated passengers arriving in Portugal from Britain must quarantine for 14 days.
That's according to a Portuguese government statement issued late on Sunday.
The new rule, which will remain in place until at least July 11, comes amid a surge in cases in Portugal, where the number of daily new COVID-19 infections is back to February levels, when the country of just over 10 million was still under a strict lockdown.
Daily positive cases have also been rising in Britain for a month. Britons arriving in Portugal by air, land or sea must show proof they are fully vaccinated or self isolate for 14 days at "home or at a place indicated by health authorities."
Britain, one Portugal's biggest sources of foreign tourists, removed the southern European destination from its quarantine-free travel list earlier this month.
Portugal is on Britain's amber list, meaning holidaymakers must self-isolate for 10 days when they return home and take expensive COVID-19 tests.
Portuguese health authorities have blamed the more contagious Delta variant, first identified in India but rapidly spreading in Britain too, for the recent rise in infections.


Trump backs down on Greenland tariffs, says deal framework reached
New Zealand rescuers seek landslide survivors as weather havoc kills two
3 people shot dead in eastern Australia, town in lockdown
Death toll in Karachi mall fire climbs to around 50, official says
Rescuers search for survivors after landslide at New Zealand campsite
