Lac d'Aiguebelette

The Lac d'Aiguebelette covers 5.45 km² (545 ha) at an average altitude of 373 m, with a mean depth of 30.7 m and a 71 m pit near the Aiguebelette-le-Lac port. The tourist office presents it as 'one of the warmest natural lakes in France': its surface waters 'can reach 28 °C in summer' — which was precisely the reading displayed in mid-August 2026. Its blue-green summer colour and its name — 'beautiful little waters' — do the rest.

Its distinctiveness is regulatory as much as natural: petrol-engined craft are strictly forbidden (the 1967 date that circulates appears on no official page, so we do not print it), speed is capped at 9 km/h, and the lake — privately owned — requires a navigation fee (€7 a day without motor). Since March 2015 the lake, marshes and reed beds form an 844 ha regional nature reserve, co-managed by the CCLA and the Conservatoire d'Espaces Naturels de Savoie, within the Chartreuse regional nature park.

Summer for swimming — six beaches, and every classified site on the lake is rated Excellente in the 2025 departmental bathing-water rankings —; the calm water suits rowing all year: the departmental base, owned by the Département and opened in 1985, hosted the World Championships in 1997 and 2015. Within the reserve, fires, barbecues, camping and bivouacs are forbidden, and dogs go on a leash.