Sandvatnet or Kaldfjorden or Øyvatnet is a lake in Innlandet county, Norway. The 19.18 km2 lake is rather unique because it has three parts and each part has a different name. Sandvatnet is the western part, Kaldfjorden is the central portion and Øyvatnet is the eastern part. The lake lies in Nord-Fron, Sør-Fron and Øystre Slidre municipalities. Water enters from the nearby lake Vinstre to the west. The lake sits at an elevation of 1019 m above sea level. The lake is located about 40 km southwest of the town of Vinstra and about 20 km northeast of the village of Beitostølen. The lake marks the northwestern boundary of Langsua National Park.