Barclays is set to open branches within Asda stores, shutting down existing sites and shifting staff to the supermarket.
The pilot will see four supermarket branches open in February, offering services seven days a week during Asda opening hours.
Barclays employees will be on hand to help customers during normal bank opening hours, with self-service machines allowing shoppers to pay in cash and cheques, pay bills, and withdraw and transfer money the rest of the time.
The branches will be in Cheshire, West Yorkshire, Hertfordshire and East Kent and Barclays aims to extend the pilot to another four stores by early 2014.
Steve Cooper, head of Barclays retail bank, says: "Our ambition is that by 2017 we will have an innovative and future-proof suite of branches that exist alongside a choice of ways our customers can contact us."
The news comes a week after Barclays chief Antony Jenkins hinted that branch closures could be on the cards for the bank in an attempt to cut costs and embrace the growing use of mobile banking services.
Tesco and Marks & Spencer - which unlike Asda offer their own banking services - have both begun introducing in-store bank branches in recent years.