Branches are being shuttered in Ballynahinch, Crumlin, Downpatrick, Glengormley, Kings Road, Ormeau Road and University Road in Belfast, Lisnaskea, Lurgan and Waterside.
The closures, which will happen next year, will leave the bank with 25 branches. The lender said there would be no further closures until at least 2026.
An Ulster Bank spokesperson said: “As with many industries, most of our customers are shifting to mobile and online banking, because it’s faster and easier for people to manage their financial lives.
“We understand and recognise that digital solutions aren’t right for everyone or every situation, and that when we close branches we have to make sure that no one is left behind.
“We take our responsibility seriously to support the people who face challenges in moving online, so we are investing to provide them with support and alternatives that work for them.”
It said it would be investing over £3m in its remaining branches over the next two years, following £3.25m of investment this year.
“We will be making no further changes to our branch network until at least 2026,” the spokesperson added.
Alliance Party MLA Peter McReynolds said he was “disappointed” that the branch at Kings Road in his east Belfast constituency would be shutting.
“This bank is located in a busy residential area, behind the thriving King’s Square which is full of busy local businesses – not to mention the impact this will have on affected staff.”
DUP Newry and Armagh MLA Carla Lockhart said the closure of the Lurgan branch leaves another gap in banking in the town.
“I have been liaising with them and unfortunately this decision is based on the decline of walk in customers and a change in how people choose to bank.
“They will be communicating this with their customers over the next number of weeks and months and are promoting the use of the local Post Offices for all banking needs.
“If you have any concerns or queries please get in touch and I will raise them directly with management.”