Opened in 1931, Chester Zoo is one of the UK's largest, spanning 111 acres. It is currently operated by the North of England Zoological Society.
The zoo claims to be the most-visited wildlife attraction in Britain with more than one million visitors.
Jennifer Tegg, marketing nanager at Chester Zoo, said: "Carat impressed us with their knowledge and understanding of our sector and brand and we are looking forward to working with them, as an extension of our team, to make our budgets go further."
Mediacom was the offline incumbent and Code Computerlove previously handled its digital media, with AKA also involved in the pitch.
In a further boost to Carat’s client base, the agency is now working with Kavli, which owns and manufactures the Primula cheese product range in the North East after a battle John Ayling & Associates.