Santander is to create a call centre with 200 staff in Liverpool as part of its rapid expansion into the UK.
The Spanish bank is also establishing new call centres in Leicester and Glasgow, with 100 staff in each. Santander has 25 million customers in the UK and 1,300 branches, employing 22,500 staff.
In 2008, Santander acquired Abbey, Alliance & Leicester and parts of Bradford & Bingley.
The new jobs will be created within an existing office in Bootle acquired as part of the takeover of Alliance & Leicester.
Nigel Cotgrove, national officer of the Communication Workers Union: "This is welcome news for the UK banking sector and provides valuable new job opportunities in Liverpool, Leicester and Glasgow."
The company reported UK pre-tax profits up 10% to £875m for the first six months of 2010.