Prime Minister Antonio Costa said the new lanes would be opened at Faro airport in the Algarve and Funchal airport on the island of Madeira — both popular destinations for British holidaymakers.
The lanes for UK nationals will be similar to those provided to tourists from the EU, he said.
British holidaymakers are important to Portugal as they are the biggest group of tourists to the country. However, numbers have dipped recently as the pound has fallen against the euro amid concerns over Brexit.
Portuguese Economy Minister Pedro Siza Vieira also sought to ease Britons’ worries this week, saying they wouldn’t need a visa even in the event of a no-deal Brexit.
He also said British citizens living in Portugal would retain all their rights after the UK leaves the EU, including access to healthcare.
“We are ready to do this unilaterally,” he told Reuters, adding that he hoped the UK would do the same for Portuguese people.
Portugal and Britain are the world’s oldest allies, having forged relations through a 1386 treaty.