The agency will also review the sites' architecture and develop a strategy around maximising user- generated content across the network.
Robert Hardie, managing editor for Associated Northcliffe Digital, said: "We'll be working with E3 to ensure we can capitalise on the sites' very loyal and active user base.
"Ten years after its initial launch and after so much organic growth, it's now time to review the ['This Is'] network to ensure it can be even more successful going forward."
Stuart Avery, joint managing director at E3, said E3 will carry out user research to form the basis of the redesign for the sites, which represent newspapers including the Nottingham Evening Post, the Bristol Evening Post and the Kent & Sussex Courier.
He said: "We'll be exploring the whole user experience including how visitors navigate their way around the site and how they search for content. Sites with this sheer amount of information must offer multiple paths to cater for different user preferences.
"We plan to investigate the use of web 2.0 approaches to enhance the findability of information such as user-generated tagging and promoting stories based on ratings and comments as opposed to traditional editorial decisions."E3's other clients include Orange, Kia, the BBC and First Plus.