Cave diving in the Doubs and Jura

• Access: for most French springs we found no diving ban, but no current access rules either. Ask the municipality (mairie) and the caving committees beforehand: CDS 25 (Doubs, speleo-doubs.com) and CDS 39 (Jura, juraspeleo.ffspeleo.fr); we found no public page of a cave-diving commission for either. Known rules: Source du Planey (authorisation from the mairie of Anjeux and the gendarmerie, barrier key), Source de l'Ain (old rule: phone the Nozeroy gendarmerie), Source du Dard (only through the Grottes de Baume show cave). • CDS 25 keeps a list of caves with access agreements and of closed caves, and points to the region's regulatory map (cartes.ternum-bfc.fr). • Switzerland: diving the Orbe resurgence at Vallorbe (VD) is not prohibited, but since 2020 the municipality and Grottes de Vallorbe SA set conditions: park at the main car park by the La Dernier power station, no driving to the spring, dive at your own risk. • Water and season: cold (Orbe 4–13 °C, Planey 11 °C): drysuit. The springs react strongly to rain and snowmelt (Loue up to ~100 m³/s, Lison up to 89 m³/s, Orbe up to 80 m³/s). In March 2012 (snowmelt, Loue) and October 2013 (floods, Lison) this stopped the diving: plan after a dry spell. • Emergency: 112 (France and Switzerland). Cave accident in the Doubs: the prefect triggers the rescue plan after consultation between the fire brigade, the prefecture and a technical adviser of the Spéléo Secours Français (SSF 25); CDS 25 publishes a contact sheet and an alert form, and there is the SSFAlert app. DAN Europe: +39 06 4211 5685. • Hyperbaric chamber: CHRU Jean Minjoz, Service d'Oxygénothérapie Hyperbare, 3 boulevard Fleming, 25000 Besançon (~1 h from Pontarlier). Tel. +33 3 81 66 89 13 (or +33 3 81 66 81 66, ext. 68913). Mon–Fri 8:30–16:30, 24/7 on-call for emergencies outside those hours. One treatment chamber for one recumbent patient per session (as of December 2023). • Gas: we found no public fill station for visitors in the Doubs or the French Jura. Trimix at DiveStation in Neuchâtel (~55 min) and at plongee.ch in Puidoux near Lausanne (~1 h 15), both in Switzerland. O₂ and helium: ask beforehand or bring your own. • Non-diving day: the dry Grottes de Vallorbe (show cave at the Orbe resurgence), the walk to the Source de la Loue (Maison de la Source, open daily July–August) and the Source du Lison with the Creux-Billard and the Grotte Sarrazine (climbing at the Porche Sarrazine/Creux-Billard banned since 2021). Register the Verneau traverse (dry cave) with CDS 25.