It is offering three-year discounts on its three interest-only products which are available up to 50%, 75% and 85% LTV.
All rates will convert to the lender’s SVR, which is at 4.99% once the discount has expired.
Principality is offering a rate of 3.39% on its 50% LTV deal, down from 3.59%, and a rate of 3.99% on its 75% LTV deal, down from 4.49%.
Its 85% LTV deal has seen the rate slashed from 4.69% to 4.39%.
All products include a fee of £900 and a mortgage commitment fee of £99.
A spokesman for Principality said: “We reduced rates across the range, in line with competitor and market movements.”
Principality’s interest-only products are available across all channels, including intermediaries.