Switzerland
Lac souterrain de Saint-Léonard
Closed to divers
Not open to divers: it is a show cave with boat tours; only exceptionally, through the operator, was a dive club once allowed in (2014).
- Max depth13 m
- CertificationCavern
Diving and fills
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Fills nearby
- Fill stationDive Center Thunersee (Hilterfingen)In the shop: air, nitrox, trimix, O₂ and argon (per the SSI listing). Outdoor fill station: air or nitrox 36% to 200 bar.Route ↗
- Fill stationplongee.ch (Puidoux/Rivaz, Zwitserland)Air, nitrox, heliox, trimix, O₂ and helium; 200 and 300 bar outletsRoute ↗
- Fill stationNemo Tauchsport (Heimberg)Air, in the shop and 24/7 at the outdoor fill station (with a Nemo fill badge); nitrox only in the shop, price on requestRoute ↗
Now at Lac souterrain de Saint-Léonard
What it looks like
Plongée au lac souterrain de Saint-Léonard / Diving in the underground lake of Saint-Léonard Plongée - Lac souterrain de Saint Léonard Plongée dans le lac souterrain de Saint Léonard, Valais 🇨🇭
All 4 videos and posts
Videos and posts
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Plongée au lac souterrain de Saint-Léonard / Diving in the underground lake of Saint-Léonard Plongée - Lac souterrain de Saint Léonard Plongée dans le lac souterrain de Saint Léonard, Valais 🇨🇭
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Other people's footage, not advice: how someone else dives here says nothing about what suits your team. Dive within your training.
The dive
Europe's largest natural navigable underground lake lies in gypsum. It was discovered in 1943 and boat tours have run since 1949; the water level dropped after the 1946 earthquake.
Profile and sections
Europe's largest natural navigable underground lake lies in gypsum. It was discovered in 1943 and boat tours have run since 1949; the water level dropped after the 1946 earthquake. It closed in 2000 for works to secure walls and ceiling, then reopened.
- Depth and profile
- Lake ~260–300 m long, up to 29 m wide, max -13 m · cave ~1.4 km in total
- Configuration
- Large, shallow underground chamber: any configuration fits (estimate). Water 11 °C.
- DPV: Not DPV-suitable (estimate)
- Small, shallow lake: no reason for a scooter (estimate).
Who can dive where
- At least Cavern
- Configurations: Backmount / twinset / Sidemount / CCR / Small cylinders / no-mount (speleo sumps)
- Goes down to 13 m (trimix or deco may be needed)
This is how the planner decides who in your team may dive this cave. Rules your own trip adds (organizer, a mail, the AI) show with your trip.
How to get there
Show cave with ~30 min boat tours (2026 season: 19 March–1 November, daily 10:00–17:00, online booking compulsory). Not open to divers; a Swiss dive club was once exceptionally allowed to dive (2014 report). Permission only through the operator.
Around Lac souterrain de Saint-Léonard
Fills3 fill stations · nearest 56 km
Dive Center Thunersee (Hilterfingen)
Hübelistrasse 1, 3652 Hilterfingen, Switzerland
In the shop: air, nitrox, trimix, O₂ and argon (per the SSI listing). Outdoor fill station: air or nitrox 36% to 200 bar.
Wed–Fri 16:00–20:00, Sat 8:00–16:00; closed Mon, Tue and Sun. Other times by phone appointment.
Dive centre on the north shore of Lake Thun, on the same side as the Bätterich. Rebreather support, rentals (incl. drysuits and cylinders) and technical courses. Trimix and O₂ fills for visitors: ask in advance.
plongee.ch (Puidoux/Rivaz, Zwitserland)
Route du Verney 18, 1070 Puidoux, Switzerland
Air, nitrox, heliox, trimix, O₂ and helium; 200 and 300 bar outlets
Mon–Fri 9:00–12:00 and 13:30–18:30, Sat 9:00–16:00; air station 24/7 for subscribers
Dive shop in Puidoux (Rivaz); one of the most complete gas lists in the area. Air-station subscription CHF 180 a year (couple CHF 290); air CHF 6–12 per cylinder, +CHF 2 for 300 bar. Walk-in trimix fills for visitors: ask.
Nemo Tauchsport (Heimberg)
Stationsweg 7 (Zentrum Lädeli, 1. UG), 3627 Heimberg, Switzerland
Air, in the shop and 24/7 at the outdoor fill station (with a Nemo fill badge); nitrox only in the shop, price on request
Mon 18:30–19:30, Tue–Thu 17:30–18:30, first Saturday of the month 9:00–14:00, other Saturdays 9:00–12:00; other times by appointment. Outdoor fill station (air) 24/7.
Dive shop and PADI school in the Zentrum Lädeli shopping centre (by the Aldi, first basement level) in Heimberg, near Thun. Air CHF 10 per cylinder; only cylinders with a valid Swiss test. The outdoor fill station needs a fill badge: ask in the shop.
Caves nearby1 within 56 km
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