Last Thursday’s announcement (26 August) saw Canada, Denmark and Switzerland added to the green list while Thailand and Montenegro were demoted to the red list.
Since the update, Your Co-op Travel said the three most searched for destinations through its website were Malta, Croatia and Majorca.
Mainland Spain, the Balearics, Canary Islands, Greek Islands and Cyprus have also seen an "uplift" in bookings and enquiries for travel in September and October 2021.
The agency is also offering its members discounted PCR and antigen travel tests, supplied by government approved firms Randox and C19 Testing, from £48 and £21 respectively.
Sara Dunham, chief officer for travel and leisure for The Midcounties Co-operative, said the company is anticipating that the stabilising of the green and amber lists will "inspire a rush in autumn bookings".
"Customers are seeing that it is possible to enjoy a much-needed holiday this year and confidence is growing thanks to the various protections that trusted travel companies like Your Co-op Travel have in place," she added.
"With the addition of our partnership with Your Co-op Pharmacy we continue to offer our customers the very best guidance, support and prices."