Talks are ongoing between the UK and Portugal after it was left off the official 'air bridge' list.
Holidaymakers from England can visit 73 destinations with no mandatory quarantine upon their return - including Spain, Italy, France and Malta.
But isolation measures were not lifted for Portugal and The Foreign has not changed its advice warning against all but essential travel, apart from Madeira and the Azores.
Now talks are ongoing between Portuguese and British authorities ahead of an evaluation of the list - which could see the country added.
Prime Minister Antonio Costa said: "The foreign minister had a long conversation with his counterpart
"It is very important we build a confident relationship."
Transport Minister Grant Shapps said on Monday that the decision to not include Portugal will be reviewed by July 27.
"We have maintained permanent contact with the United Kingdom," Costa added.
The exclusion was a major blow for the country's tourism sector - with 2.1 million Brits visiting Portugal every year.
The decision is set to further damage the country's tourism-dependent economy, especially the southern Algarve region.
Over a dozen countries have imposed restrictions on visitors from Portugal due to a spike in coronavirus infections.
Several hundred new cases per day in a region on the outskirts of Lisbon in the past month has worried authorities.
Overall, the country has only reported 1,629 fatalities, which it attributes to its high testing rate.
Following the announcement on Friday that the country would be excluded, the Portuguese foreign affairs minister branded it “absurd” that it had been left off the list.
Portugal’s prime minister Antonio Costa tweeted a graph appearing to show the UK had a much higher number of cases per 100,000 population than the Algarve.
He said: “Which is the safest place to stay? You are welcome to spend a safe holiday in Algarve! #UK #visitportugal.”
