The new office will be fully staffed and concentrate predominantly commercial and IT law, claims resolution, commercial property and planning and employment law.
Partners Nigel H Williams, Richard Ottley, Emrys Parry and Glynis John - who head the relevant departments - are likely to spend at least one day a week at the new office.
Christopher Eskell, managing partner of the 15-partner firm says: "An increasing proportion of our client are either Welsh based or have Welsh offices, and therefore we believe that support is important on the ground.