The rolling average case rate on the islands has reportedly doubled in 10 days to 84 per 100,000 people.
Formentera has experienced the highest numbers at 109 – although this is still lower than the UK’s 184.
The Spanish islands were added to the UK’s "green watchlist" on Wednesday (30 June), meaning they could be relegated to the amber list at short notice should the government see fit.
British travellers need to be double-vaccinated or have a negative PCR test before entering.
The islands reportedly began vaccinating those aged 16-29 this week.
