Popular holiday destinations Ibiza, Majorca, Menorca and Formentera will be moved to the UK government's amber travel list from July 19.
On Wednesday, Britain’s transport secretary Grant Shapps announced that the Balearics would join the list from 04:00 BST on Monday, just 15 days after being placed on the coveted green list.
It means that anyone returning to the UK from Spain after July 19, will need to self-isolate for 10 days. However, those who have been fully vaccinated would not need to quarantine although they will still need to undergo testing before travelling to the islands and on their return.
It’s believed that many of up to 200,000 already holidaying on the islands since they were placed on the green list, will be under 30, they will not have been fully vaccinated and will therefore need to quarantine on their return under the new measures.
Wales and Scotland have already announced that they will follow suit with Northern Ireland likely to do the same in the coming days.
Mr Shapps said that the updates were “guided by the latest data” and urged travellers to “check the latest travel advice before you travel as countries and territories may have extra requirements before you get there”.
The news will come as a bitter blow to the islands, which are one of the most popular tourist destinations for British holidaymakers.
Paul Charles, from the PC travel agency voiced his frustration over the UK government's traffic light system saying, “The policy implemented by the government needs to change. It is not at all useful for the consumer if the colour of a country is changed in barely two weeks. This traffic light system is not working.”
It follows a recent increase in Coronavirus cases in the Balearics thought to have been fuelled by end of term school parties and social gatherings.
France and Germany also recently advised against travel to Spain due to the spike in infections, thought to be driven by the spread of the more contagious Delta variant.
Recent data from the Spanish Ministry of Health shows that infection rates for the largely unvaccinated groups between the ages of 12 and 29 are around three times higher than the national average.
Incidence rates for the Balearics have almost doubled in recent days with the cumulative incidence per 100,000 inhabitants over the last 14 days reaching 408, compared to the national average of 469. This is way above the Health Ministry’s 'extreme risk' threshold of 250.
Over 22 million Spaniards have now been fully vaccinated against the virus, the latest ministry data shows accounting for around 47% of the population.
On Wednesday, the ministry published their latest figures which showed that there had been a further 26,390 new infections and another 10 fatalities.
This brings the total number of infections since the pandemic began to 4,041,474 with 81,043 deaths.