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🌲 Saint-Léonard Undergroung Lake

Rue du Lac 21, 1958 Saint-Léonard
Phone 1
2016 June, 2018 Août
  • Date de Visite
    26.06.2016 && 19.08.2018

logo Saint-Léonard underground lake

The Saint-Léonard underground lake

The Saint-Léonard underground lake (Lac souterrain de Saint-Léonard in french), near Sion, is the largest underground and navigable lake in Europe. It was formed in the 1940s following an earthquake that caused cracks and a lowering of the water level that filled the cave. The entrance to the cave is through the small refreshment bar.

The entrance to the Saint-Léonard underground lake.
The entrance to the Saint-Léonard underground lake.

The cave

The cave is located a few dozen meters under the vines and receives its water by rustle of rainwater and emerges through cracks. The cave was formed by the dissolution of Gypsum, a rock that dissolves over time in water. Other rocks such as marble provide waterproofing. The dimensions of the cave are 300 meters long and 10 meters high. The temperature inside the cave is about 15 degrees. A lot of information in three languages is available on the official website.

A butterfly on the walls of the cave.
A butterfly on the walls of the cave of the underground lake of Saint-Léonard

The access

It is possible to park below the entrance of the lake at 5-10 minutes walk.

The parking to access the saint-léonard underground lake

The visit

Visits to the lake date back to the 1950s just after the lake appeared. Access to the cave is via a refreshment bar where you can have a snack. The visits last about 45 minutes and take place approximately every hour with a multilingual guide in boats of about 20 people. The lighting of the cave allows to discover its structure and the different layers of rock that make it up. We are surprised by the calm and transparency of the lake’s waters. It is about 2 metres deep and contains fish that have been introduced to monitor the cleanliness of the water.

The boats used for the visit and a boat with visitors.
The boats used to visit the underground lake of Saint-Léonard  a boat with visitors to the underground lake of Saint-Léonard

The concerts

Once a month concerts take place from a boat that you can see when you visit the cave which has excellent acoustics. Aperitifs can also be taken on reservation.

The boat from which concerts are organised.
The boat from which concerts are organised at the saint-léonard underground lake

Sion and Saint-Léonard

The underground lake of Saint-Léonard is close to Sion and its emblematic figures of Valère and Tourbillon, which can be visited before or after.

Valère and Tourbillon
Valère near Saint-Léonard underground lake Tourbillon castle near Saint-Léonard underground lake



Related attractions

Attractions in the canton of Valais
Attractions in the Sierre region

Natural curiosities in french-speaking Switzerland

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Age 12-18
AGE 3-6 years
Age 6-12 ans
Age Adulte
Disabled People
Location Inside
Location Outside
Price 0-15
Price 15-50
Price 50+
Price Free
Rating 4/5
Rating 5/5
Season Winter
View ★★★
View ★★☆
View ★☆☆