Grottes des Moidons

Useful Information

Location:	Route d'Arbois, 39800 Molain Poligny. 10 km from Arbois. (46.8384409, 5.8066403)
Open:	APR to JUN Mon-Tue, Thu-Sun 11-17:15, tours at 11:15, 12:15, 14:15, 15:15, 16:15. JUL to AUG daily 10:30-18:30, tours every 30 min, last tour 17:30. SEP Mon-Tue, Thu-Sun 11-17:15, tours at 11:15, 12:15, 14:15, 15:15, 16:15. [2024]
Fee:	Adults EUR 10, Children (13-17) EUR 8, Children (4-12) EUR 7, Children (0-3) free, Students (-26) EUR 9. [2024]
Classification:	Karst Cave
Light:	LED Son et Lumière Regenerative Electricity
Dimension:	T=10 °C.
Guided tours:	D=50 min. V=53,000/a [2023]
Photography:	allowed, no flash
Accessibility:	no
Bibliography:	Fabien Borderie, LaurenceAlaoui-Sehmer, Faisl Bousta, Badr Alaoui-Sossé, Lotfi Aleya (2014): Cellular and molecular damage caused by high UV-C irradiationof the cave-harvested green alga Chlorella minutissima: Implicationsfor cave management, International Biodeterioration & Biodegradation, 93 (2014): pp 118-130. researchgate online DOI
Address:	Grottes des Moidons, Route d'Arbois, 39800 Molain Poligny, Tel: +33-384-517494. Office de Tourisme Arbois, 17 rue de l’hôtel de ville, 39600 Arbois, Tel. +33-384-73-01-34.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then. Please check rates and details directly with the companies in question if you need more recent info.

History

1966	discovered by Fred Meyer and Pierre Murat.
1989	opened to the public.
APR-2013	new entrance tunnel.
MAR-2024	a fire destroys the reception building, cave closed for renovation.
Spring 2025	scheduled reopening.

Description

The Grottes des Moidons is located in the middle of the forest of Moidons, after which it was named. As it was discovered in 1966, the use of the Smile Pluralis Absurditatis in the name is rather weird, fortunately this strange habit from the 18th century is now almost extinct. The cave is located far from the next settlement in the forest, the hamlet Molain is 1.5 km to the south. It is reached on a single lane road which ends at the cave. The cave entrance is the starting point of several nature trails with educational signs. There is the Ammonite café, a souvenir shop, picnic area and children's playground.

It is praised as the only show cave in the Jura which is illuminated with solar energy. And they even have enough electricity to charge your e-bike during your tour. The cave is actually connected to the electric grid by a surface line from Molain. But it seems they installed a new LED light system which was powered by solar cells. Unfortunately they do not mention the solar power on their website, and we have no technical details, so we were not able to list the cave on our Explain Regenerative Electricity page. They use the rainwater from the roof for the toilets and even for the dishwasher, and they have a green roof. The soil and plants provide insulation, and keep the temperature low even during the summer heat. However, in spring 2024 the whole entrance building was destroyed by a fire, including the solar cells, batteries and the green roof. The cave was closed for the full season while a new building was erected. We will check back next year after the reopening.

The cave is entered in the middle, which is a huge chamber called Main Chamber. Here the trail splits, the right one into the North Gallery, the left one into the South Gallery. Both are dead ends, and so it is necessary to return the same way. The cave is well decorated with stalagmites, stalactites, draperies, and pillars. There are even some ponds with rimstones. The ponds are the location where the son et lumière is shown.

The Grotte des Moidons is owned by the Domaines, which is the French State, and it is managed by the Office National des forêts (ONF, National Forestry Office). The cave was opened to the public in 1989, at this time the natural entrance was used. This natural entrance is a vertical shaft in which a spiral staircase with 80 steps led down to the floor. Isabelle and François Gauthier, both cavers and cave guides, made a 30-year lease of the cave. The lease was renewed for another 30 years a few years ago. In 2013 a new artificial entrance tunnel was opened which allows easy access. François Gauthier dug the tunnel over six years during the winter closure of the show cave, using "mini-explosives and the strength of his arms". The new entrance tunnel made the cave tour almost level and comfortable, it's actually possible to visit the cave with strollers. The cave is not wheelchair-accessible though, there are no stairs but several steep ramps, so it works only for light persons, especially children, with someone strong enough to push the wheelchair. It's allowed to take pets on the tour, as long as they behave. The guided tour takes about 50 minutes and includes a short film, a guided tour through the cave, the mandatory son et lumière show. There is also a sort of bat-zoo, where it is possible to see those cave visitors sleeping during the day. This is quite popular with children, who also enjoy the maze.