Alpine Lake / Ata Puai is a small lake in the West Coast Region of New Zealand. The lake is located south of Okarito and west of the larger Lake Mapourika. "Alpine" is something of a misnomer as the lake is only from the sea and at an elevation of less than 100m.

Alpine lakes are classified as lakes or reservoirs at high altitudes, usually starting around 5,000 feet (1524 metres) in elevation above sea level or above the tree line.

Alpine lake is a class of lakes found at high altitudes.