Cave diving in the Vercors
Sump diving in the big Vercors springs (Goule Noire, Bournillon, Cuves de Sassenage: chains of sumps behind dry passages, low water only) and guided dives via Vercors Plongée in the Grotte de Thaïs and the lake of the Grottes de Choranche; two Drôme springs are off limits (drinking water).
7 caves · down to 137 m · 2 suitable for an intro team
All 7 caves
| Site | Max depth | Type | Certification |
|---|---|---|---|
| Cuves de Sassenage | – | Not known yet | Full cave |
| Émergence de Bourne⛔ Closed to divers | 32 m | Not known yet | Full cave |
| Grotte de Bournillon | 85 m | Sidemount | Full cave |
| Grotte de Thaïs | 97 m | Sidemount | Intro to cave (first section) |
| Émergence du Diable⛔ Closed to divers | 137 m | Not known yet | Full cave |
| Goule Noire | 20 m | Sidemount | Full cave |
| Lac des Grottes de Choranche | – | Backmount | Cavern |
Certification requirements, configurations and trimix depths are estimates for planning. Always check them locally and dive within your training.
Practical info: rules, fills and emergency numbers
Emergencies
- 112 (or 15 SAMU, 18 fire brigade); say it is a cave-diving accident. DAN Europe: +39 06 4211 5685.
- Hyperbaric chamber: Hôpital Édouard Herriot, 5 place d'Arsonval, 69003 Lyon, tel. +33 4 72 11 00 31, 24/7 (~1 h 45 from Pont-en-Royans, estimate). The number comes from the chamber list on the FFS site (updated in 2007): check it beforehand.
Access and rules
- Access: no central scheme. The Grotte de Thaïs and the lake at the Grottes de Choranche are on private show-cave land (Visites Nature Vercors): dive through Vercors Plongée, or for Thaïs only with the manager's permission. The Émergence de Bourne (Beaufort-sur-Gervanne) and the Émergence du Diable (Échevis) are tapped for drinking water: diving banned. The Goule Noire is a protected site (site classé, 1911) in the Parc naturel régional du Vercors; no diving ban is known for the Goule Noire or the Bournillon.
Gas and fills
- Gas and rental: Vercors Plongée (Royans, near Saint-Thomas-en-Royans) fills air, nitrox and trimix by appointment; oxygen available, helium on request; rents drysuits, 12/15 L cylinders and lights. CCR absorbent and CCR or scooter rental: not mentioned, ask.
Water and season
- Water and season: 5–7 °C in the Goule Noire and the Bournillon, ~10 °C in Thaïs (the dive centre quotes 13 °C): drysuit. The springs react violently to rain and snowmelt (Goule Noire up to 34 m³/s, Bournillon up to 80 m³/s). The Goule Noire is dived at low water in cold, dry winter spells, not during a thaw. The Bournillon sumps can only be reached after a long drought (in 2010: 'once every five years'). Plan for a stable dry spell and watch for thunderstorms.
- Altitude: Goule Noire 680 m, Choranche lake ~600 m, Bournillon 418 m, Thaïs 176 m. At the higher springs, check your computer's or tables' altitude setting.
Rest day
- Non-diving day: the show caves of Choranche (open all year) and Thaïs (April–August), the Cuves de Sassenage (show cave in summer, guided caving all year) and in the Dévoluy the 5 km walk to the Sources des Gillardes (861 m), one of the most powerful springs in France.
Good to know
- Character: the big springs (Goule Noire, Bournillon, Cuves de Sassenage) are sump dives: chains of sumps behind dry passages, waterfalls and carries, with small cylinders or sidemount, and only at low water. For an ordinary dive day there are the guided dives in Thaïs and the Choranche lake.
- Federations and clubs: cave diving falls under the FFS (École Française de Plongée Souterraine: courses, regional correspondents, accident reporting) and the FFESSM (Commission nationale plongée souterraine). Isère caving committee: CDS 38. The FFS site plongeesout.ffspeleo.fr has sheets and reports on over 40 sumps in the Isère and the Drôme.
Plan a cave diving trip to the Vercors
Enter your team, with certifications, gas and configurations, and see right away which caves fit. With driving times from your stay, fill stations and an AI instructor who thinks along.
Compiled from public sources: the FFS site plongeesout (site sheets, reports, chamber list), Spelunca, Vercors Plongée, Visites Nature Vercors, Wikipedia, grottomap, DREAL Auvergne-Rhône-Alpes, CDS 38, Vercors Vertical, gouffre-berger.com, Vercors-Drôme tourism, plongeur.com, altituderando and decathlon-outdoor (September 2026). Much of the dive data comes from exploration reports (1997–2010) and sometimes differs between sources. Pins from Wikipedia, grottomap, the tourism database, the plus code of a meeting point and two converted Lambert III coordinates; one site without a pin. ~ = estimate. Rules change — check locally.