Lake St Clair is a lake in the Central Highlands area of Tasmania, Australia. It forms part of the Cradle Mountain-Lake St Clair National Park. It has an area of approx 45 km2 (17 sq mi), and a maximum depth of 160 m, making it Australia's deepest lake.
The Tasmanian Government has moved to allow development in national parks and conservations areas. An 'In principle' permit has been granted for the establishment of an 'eco-friendly' resort at Pumphouse Point at Lake St Clair. Construction began on the new development in 2014.