Portugal will allow tourist flights from European Union countries with low infection rates and from the UK, but passengers must show a negative coronavirus test on arrival, the Interior Ministry said on Saturday.
The announcement came a day after the Portuguese tourism authority gave the green light to UK tourists to enter the country from Monday.
In a statement, it said the ban will be lifted on European countries with less than 500 cases of infections per 100,000 people.
Tourists from Liechtenstein, Norway, Iceland and Switzerland are also allowed to start flying to Portugal.
Visitors will have to show proof of a negative test taken up to 72 hours before a flight and airlines will be fined between 500 euros ($607) and 2,000 euros for each passenger who boards without presenting proof of a negative test.
Portugal currently only allows essential flights for professional, study, family reunion, health or humanitarian reasons.
Travellers from countries where 500 or more cases per 100,000 people have been reported over a 14-day period can only enter Portugal if they have a valid reason, such as for work or healthcare. Arrivals must then quarantine for 14 days.