Boats on Subterranean Lake






Europe's largest subterranean lake that can be sailed upon lies between Sion and Sierre. The water grotto is easily accessible and there is a boat tour for viewing it. The guides on the boat tell visitors about the history of the cave and its geology.

Group activities

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1/2 day

20 - 120


Whole year

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Various types of stone glitter at a height of ten meters, their shapes reflected on the 6,000 square meter surface of the lake. Trout swim in the clear water and the only species that is actually native to this subterranean world, the fungus gnat, hangs its larvae upside down on the walls of the cave.

Viewing the subterranean lake of St-Léonard is a marvelous adventure. The 300 meter long and about 20 meter wide watery underworld is considered to be a place of special power. It has been accessible to tourists since 1949. Every year about 80,000 visitors are taken in large boats to see the lake. The famous speleologist Jean-Jacques Pittard is said to have been the first person to scientifically explore the cave.

The grotto can be rented for special occasions.

RailAway combined group offer

  • From the Rail Service Helpdesk 0900 300 300 (CHF 1.19/min. from the Swiss fixed-line network)
  • At railway station ticket counters

We recommend that you book early, i.e. at least 1 week before the start of your journey. Please note: You can only obtain this reduced RailAway combined offer at the points of sale given above.

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