Spain has said it is officially lifting restrictions for UK travellers from Monday, when a decree takes effect.
The government says the UK and Japan will be on a list of countries whose residents are able to avoid restrictions on non-essential travel to the EU. They will not need a PCR test.
But the UK government still strongly advises against non-essential travel to Spain and most other EU countries.
UK tourists going to Spain will still have to quarantine on their return.
Prime Minister Boris Johnson's spokesman said: "We've been clear people shouldn't be travelling to amber list [nations] for the purpose of holidays. Our advice hasn't changed. We will keep the green list under review… and will add countries where possible."
Portugal is the main destination on the UK's short "green" list of countries that are free of the quarantine requirement. Under the UK's traffic light system, people are advised to avoid amber and red countries, where the Covid risk is greater.
The EU is currently deciding on an expanded "white list" of countries whose citizens can enter the EU freely.
Only seven, with very low Covid infection rates, are on the list now. Those countries are: Australia, Israel, New Zealand, Rwanda, Singapore, South Korea and Thailand.
The BBC has been told a final EU decision on expanding the list has been delayed for another two weeks.
Tourism in Portugal and Spain relies heavily on British visitors in the summer, and travellers from England, Scotland and Wales began flying to Portugal last Monday.
