Saunalahti (Finnish) or Bastvik (Swedish) is one of the newest apartment building districts in Espoo, Finland, located by the Kummelivuori hill between Kivenlahti and , west of the Kauklahdenväylä road, on the coast of the Espoonlahti bay. The bay at Saunalahti is named Bastvikfjärden. The area also contains original detached house residence from old Saunalahti and agriculture. Saunalahti is separated from Kivenlahti by the Länsiväylä highway, continuing to Kirkkonummi as Jorvaksentie.