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.


US peace envoys meet Zelenskyy in Kyiv after Putin talks
US targets three Iranian oil vessels after attack on Navy ships
Israeli strikes kill seven in southern Lebanon
Indonesia's Anak Krakatau eruption halts flights, schools, fishing
Putin says US-Russia contacts beneficial as talks begin with Witkoff and Kushner
Chinese national rescued from Nepal tunnel 10 days after flash flood
US envoys Witkoff, Kushner arrive in Moscow for talks on peace in Ukraine
One dead, 11 people missing after mudslide in China's Jiangxi province
