The affected branches are at Jordanstown, Longstone Street in Lisburn, Knock and Shaftesbury Square in Belfast, Harryville, Carryduff and Dromore in Co Tyrone.
The sub-officers are at Roslea in Co Fermanagh, Moy in Co Tyrone and Saintfield and Ardglass in Co Down.
Ulster Bank said it expects them to be closed by June.
A statement continued: "We will be contacting customers of these branches to inform them of alternative branch locations in their area. We are communicating directly with staff in those branches and there will be no additional job losses as a result of this announcement.
"Ulster Bank still has the largest network, with 79 branches across Northern Ireland."
Another 11 branches are closing in the Republic of Ireland.
It comes after the bank announced in January 2012 that 950 jobs were set to go.
Last year Ulster Bank revealed it paid out over £18m to almost 300,000 Northern Irish customers after a technical glitch left them without proper access to their bank accounts for weeks over the summer.
The staff redundancy programme was put hold while the bank dealt with the crisis.
Robin Swann of the UUP said he is shocked by the Harryville closure.
The North Antrim MLA added: "My office is across the street and the branch is clearly a very popular and busy facility. Harryville has in the past lost its main Post Office and this closure represents the further erosion of basic services from the local community."
Patsy McGlone, who chairs the Assembly's enterprise committee, called for the bank to immediately clarify how staff and customers will be affected.
"I have written to both the Ulster Bank and the Irish Bank Officials' Association (IBOA) seeking a meeting and seeking clarification on number of issues that are currently causing no little worry for staff and customers," said the SDLP MLA.
"This has already had a traumatic effect on the lives and health of many workers at Ulster Bank who face such an uncertain future. These are the same staff that, during the IT crash in 2012, had to deal with the anger of the public -through no fault of their own- with diligence and professionalism.
"What now needs to happen is that we have to establish how many redundancies there will be through phased or compulsory redundancy, or if staff will be able to seek transfers to other branches or posts."
Ian Paisley MP said he has been "categorically assured" of no job losses in the Ulster Bank withdrawal of 11 branches across NI.
"Firstly this is quite clearly an enormous disappointment for those who live within the areas that bank closures will be occurring," said the DUP representative.
"It certainly appears to represent a lack of commitment to those communities in which they serve. Next week when I meet with RBS chiefs in London I will be seeking clarification on this point which at least takes away that element of uncertainty for staff."