London, Leeds and Glasgow have been specially chosen as the three locations to be refurbished with a new tropical décor, which will run until June 27.
Costa will bring summer to the three locations with full-sized window, floor, wall and table vinyl's printed with tropical prints and flamingos. Hot pink neon signs will light up the store, while brightly patterned coasters and cushions and plants will adorn the interior.
The flagship stores will also have selfie zones where customers can pose in a Miami-themed setting complete with sun loungers, fake grass and flamingos.
Customers are also being offered the chance of winning Seriously Summer in-store pieces if they tag their selfie with #seriouslysummerselfie.
Caroline Harris, UK&I marketing director at Costa, said: "We wanted to give select Costa stores a complete revamp to celebrate the start of summer and create an engaging environment for customers to enjoy our new summer menu.
"We hope the fresh look will encourage customers to see Costa as a seriously summer destination."
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