Nine branches will close in Yorkshire and 17 more in other parts of the UK, the bank said.
It did not disclose details of any redundancies, but said affected staff would be offered other roles “wherever possible”.
The bank, which was sold off by its former parent National Australia Bank earlier this year, said the closures reflected “the changing needs of customers who want to access more day-to-day banking services quickly, on the move and outside normal business hours”.
It said 10 of its remaining branches in Yorkshire would now also open on Saturdays and 16 more would see their Saturday hours extended.
The axed branches, which will close between July and September, are in Batley, Heckmondwike, Thorne, Yeadon, Rotherham Parkgate, Ilkley, Knaresborough, Queensbury and the Leeds suburb of Seacroft.
Head of customer banking networks, Steve Fletcher, said: “I understand this will not be welcome news for those who use these particular branches. These are difficult decisions but ones we must face as we try to keep up with the pace of change in the way people want to bank. We have to balance our investment to ensure we support demand where it is greatest, across mobile, online and branch services.”
He added: “Branches remain vitally important to us, and we continue to invest in them, the services they offer and when we offer them. I hope that the investment we’re making in the overall quality of our branch network, the big increase in Saturday opening and the availability of other ways to bank, like local Post Office counters, will minimise the effect of this announcement for customers.”