The bank said a net 92 full-time staff would be affected, while 154 contractor roles will be lost later this year.
It is understood that most of the posts are technology-related and are based in London.
RBS said it was reducing the size of its back-office support as it moved towards becoming "a simpler, smaller UK-focused bank".
The union Unite claimed that as many as 334 jobs were being cut and that more roles were being transferred to India.
Some 88 roles are to be created, meaning net job losses of 246. An additional 38 new roles will be created in India.
National officer Rob MacGregor said: "Unite cannot understand how RBS, which continues to be taxpayer backed, can justify hundreds more staff cuts and continue transferring important work out of the country.
"It is wholly inappropriate and unjustified for these technology roles to be sent offshore."
RBS declined to comment on Unite's offshore claims but a spokesman said: "As RBS moves towards becoming a simpler, smaller UK-focused bank, we're continuing to restructure our back-office support and reducing its size so it's a better fit for our business.
"Unfortunately, these changes will result in the net reduction of 92 roles.
"We understand this will be difficult news for staff and we will be offering support to those affected, including redeploying people in to other roles where we can."
In February, chief executive Ross McEwan ordered a Â£2bn four-year cost-cutting drive involving job losses and branch closures.
Last month the bank, which is 72%-owned by the UK government, posted its first quarterly profit since Sept 2015.
RBS said then that its cost-cutting plan for 2017 was ahead of schedule, with 37% of the planned Â£750m of cuts achieved.
RBS is shedding nearly 250 posts, as part of an overhaul of its back-office operations.