UK travellers have been heading to Faro airport to try to get back to Britain after ministers moved Portugal from the green list to amber.
It now means that anyone flying into the UK from the country will be required to quarantine for 10 days from 4am on Tuesday.
Photographs taken at Faro Airport in the country's southern Algarve region show hundreds of UK families ignoring social distancing rules as they gathered in huge queues in the departures lounge.
There are an estimated 112,000 Brits currently in Portugal and airlines have been putting on extra flights to try to get people home. It is thought some 100 flights were expected to leave Faro on Sunday and there were long queues forming around the building with passengers trying to get away.
The move comes after cabinet ministers announced last week that Portugal will be downgraded to amber from 4am Tuesday following worries about the so-called Nepal coronavirus variant.
Health Secretary Matt Hancock said the decision on Portugal, which includes the islands of Madeira and the Azores, had to be made because of a rise in cases of the Delta variant, first detected in India.
He said: "It was not a decision I wanted to take, but we're absolutely determined to keep this country safe, especially from novel variants coming from overseas."
However, this has caused anger among travellers as it is thought at the time, just one case of the strain had been detected in Portugal, while 43 cases had been identified in the UK.
Travel industry bosses have blasted ministers for the decision and warn that it could result in job losses and have a further crippling impact on the industry which has already been hit hard by the pandemic.
Thousands of passengers leaving Faro this weekend have also had to fork out high prices to buy PCR tests so they can fly home.
With PCR tests costing £125 each, a family-of-four could be paying £1,000 for tests for which they have not planned for and this has also been criticised as many travellers are left out of pocket.