The new restriction will not apply to travellers returning from Madeira and the Azores.
The country has witnessed a surge in coronavirus infections in the Lisbon and Porto regions.
In yet another blow for Brit tourists, the government has announced Portugal, Hungary, French Polynesia and Reunion Island have been removed from England’s quarantine exemption list
Transport Secretary Grant Shapps said on Twitter: “Data shows we need to remove Portugal (minus the Azores and Madeira), Hungary, French Polynesia and Reunion from the travel corridor list to keep everyone safe.
Portugal will be added to England’s quarantine list this weekend, meaning any Brit travellers not back in the country before 4am on Saturday will be required to self isolate for two weeks upon their return.
Along with Portugal, Hungary, French Polynesia and Reunion Island have been removed from England’s quarantine exemption list.
“If you arrive in England from the Azores or Madeira, you will NOT need to self-isolate for 14 days.”
He added: “Through enhanced data we now have the capability to assess islands separate to their mainland countries.
“If you arrive in England from these destinations after 4am Saturday, you will need to self-isolate for 14 days.”
Sweden has been added to the travel corridor list, meaning Brit tourists won’t have to quarantine when they get back.
Northern Ireland has yet to impose the measures.
Wales already required returning Brit tourists to self-isolate, and Scotland includes the Portuguese islands of Madeira and the Azores under quarantine guidelines.
Shapps also reminded travellers to complete a Passenger Locator Form after getting back to the UK.
The country’s seven-day case rate currently stands at 25.8 per 100,000 people, slightly above the UK rate of 23.1.
Just weeks ago, the English government had changed the rules so holidaymakers could fly over to Portugal.