The new mortgage is available to customers with a 35% deposit and has a £1,369 product fee.
It complements its existing mortgage range, which includes a 1.29% two-year fixed rate with a £845 product fee also available to borrowers with a 35% deposit.
Mike Regnier, Yorkshire Building Society’s Chief Commercial Officer, said:
“Being a financially strong mutual which focuses on its members rather than external shareholders allows us to provide such competitive mortgages.
“We pride ourselves in doing everything we can to help people buy the home they want, as reflected by now offering our lowest ever mortgage rate at 1.18%.
“This new mortgage forms part of our wide range across the Yorkshire Building Society Group which seeks to support borrowers of all types, including those with larger or smaller deposits and first time buyers and those already on the housing ladder.”