Plansee is a lake in the Tyrol, Austria, located at 47°28′10″N10°48′20″E / 47.46944°N 10.80556°E / 47.46944; 10.80556. Its surface is approximately 2.87km² and its maximum depth is 78 metres.
It lies on Austrian Federal Highway B 179, which crosses the Ammersattel into Germany.