The Bank says the new rates are currently the lowest on the market.
New two-year fixed rates start from 1.39% at 60% LTV, 1.44% at 75% LTV and 1.69% up to 85% LTV.
Five-year rates are available from 1.79% at 60% LTV, 1.94% at 75% LTV and 2.29% at 85% LTV.
Santander is also launching a two-year fixed rate online exclusive, at 1.09% up to 75% LTV with a £1,499 product fee.
All products come with free valuation and free legals or £250 cashback.
Miguel Sard, Managing Director of Mortgages at Santander UK, said: “These new products are designed to support customers looking to remortgage and lock in to a lower rate. Not only are they market leading, they also come with the added benefit of having no upfront product fee.”