Portugal remains off the list of countries the government has exempted from quarantine restrictions.
In the changes that apply to England, travelers from Estonia, Latvia, Slovakia, Slovenia and Saint Vincent and the Grenadines will not have to isolate themselves.
It brings the list of countries that are not subject to England travel restrictions to 80 nations.
The government has also said it will update its guidelines every week, which means the rules could change while people are away.
He said people should check the tips regularly. Previously, updates were provided every three weeks.
The Portuguese government has expressed “regret” at the UK’s decision to continue to exclude it from the list of countries exempt from quarantine.
“It is a decision that is neither supported nor supported by the facts,” said the Portuguese Ministry of Foreign Affairs and State.
Spain remains on the list of countries from which people can return to England without needing to self-isolate, despite a recent increase in coronavirus cases.
Norway announced on Friday that it was imposing a new 10-day quarantine on all travelers arriving from Spain.
According to Johns Hopkins University, Spain has recorded 270,166 coronavirus cases and 28,429 deaths.
Portugal had recently imposed local lockdowns on the outskirts of its capital, Lisbon, to stem an increase in new cases.
Portugal has recorded 49,379 cases of coronavirus and 1,705 deaths.
Tourism is a major industry in Portugal and is popular with British holidaymakers, with nearly three million British visitors per year.
Aviation data analysts Cirium said 2,333 flights were due to leave the UK for Portugal by the end of August.
Paul Charles, chief executive of the PC Agency, said it was a poorly chosen government move.
“The scale of those who have to get there before the end of August is enormous. Today’s decision sows great uncertainty in the minds of those who are reserved who will seek refunds and changes and most will not get vacations. caused an uproar among operators and industry. ”
He added: “They are not ready to open Portugal when the situation is in decline, but the cases in Spain are booming, with a rapid increase in the number of cases”.