Thetford's HSBC is one of 27 across the UK earmarked for closure, it has been confirmed.
But the Lowestoft branch is set to be refurbished this year, one of 49 to get a makeover.
HSBC stated 46 jobs are at risk in 10 of the named branches with staff at the remaining branches moved to nearby sites.
The branch closures where jobs are at risk include the one in King Street, Thetford, which will close later this year.
No branches in Norfolk will see staff relocated.
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Saxmundham in Suffolk, along with Lowestoft, will be refurbished.
It follows a series of closures with North Walsham, Attleborough and Downham Market all losing their HSBC branches in recent years.
The closures come as the bank will also invest nearly £34 million in its remaining 594 branches this year.
The announcement comes as customers turn to other forms of banking, making them less reliant on using a branch, the bank said.
HSBC said nine in 10 contacts with customers now happen over the phone, via the internet or on its smartphone app, with the number of customers who use a branch falling by a third in the last five years.
Only one in every 100 cash withdrawals are made in branch at an HSBC.
"Retaining a sustainable branch network is extremely important to us and we need to ensure it is fit for the future.
"But, the way our customers bank with us has changed significantly over the last five to 10 years, and that change is something we cannot ignore," Stuart Haire, HSBC UK's head of retail banking and wealth management, said.
The first closures will be made in early July, with branches in London, Bristol, Swindon and Leigh-on-Sea set to be axed.
HSBC customers will still be able to bank in Post Office branches across the country.
Mr Haire added: "Almost every industry is affected by similar behavioural change and needs to work hard to address that.
"Photographs that were once processed in a shop have now been replaced with digital cameras and online delivery."
Earlier this month, HSBC said its global headcount would be reduced by 35,000 over the next three years.
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