Shimmins also becomes managing director of Isle of Man Bank Limited and head of its corporate banking operations in the island.
Most recently, he was head of mortgages for RBS International, with responsibility for its mortgage operations in the Isle of Man, the Channel Islands and Gibraltar.
In his new role, Shimmins takes responsibility for all operations across RBS International and Isle of Man Bank, RBS International Group said in a statement.
He also joins RBS’s Executive Committee Offshore as its Isle of Man representative.
Shimmins, a native of Scotland, has worked for RBS since 2006 and has almost 30 years’ experience in financial services.
Prior to coming to the Isle of Man nine years ago, he worked in the City of London, according to a statement issued by the bank.
RBS International Group chief executive Adrian Gill said Shimmins was an “excellent choice” to head up the Isle of Man operation.
The Isle of Man Bank operates as an independent arm of RBS. It was founded in 1865 as Isle of Man Banking Co., and became a part of the RBS Group after being taken over in 1961 by National Provincial Bank, which subsequently became a part of National Westminster Bank, acquired in turn by RBS in 2000. It currently operates 11 branches on the island.