Festival des 3 forêts, ultra-trail races in Val-d'Oise, September 2025

On the weekend of September 13 and 14, 2025, the Val-d'Oise forests are the setting for the Festival des 3 Forêts, a sporting event offering a variety of running events, from 13 to over 160 kilometers. Around Lyon, there's the famous Saintélyon, which has been adapted over the years in a number of shorter formats (and therefore more accessible to a majority of runners): in Paris, finally, in the Val-d'Oise, there's the Festival des 3 Forêts, celebrating its first edition in September 2025.

• To be read
• This week's tips in Paris and the Ile-de-France region, December 8-14, 2025
• A guide to running in Paris and the Ile-de-France region in 2025

Lovers of long distances and natural landscapes will be delighted, with no less than seven different circuits ranging from 13 kilometers (with 300 meters of positive ascent) to 162 kilometers (for 5,000 meters of D+), starting from Mériel. Linking the three largest forest massifs in the Val-d'Oise, the proposed ultra-trail takes you to the heart of the French Vexin and its picturesque villages. Along the way, you'll discover the most beautiful nuggets of our forests: the blue lake of Carnelle, the Grand Val valley, the forest of Isle-Adam...

The different routes of the Festival des 3 Forêts :

• 13km, 300 D+ climb
• 25km, 650 D+ climb
• 45km, 1,500 D+ (over 1,000 miles)
• 65km, 2,500 D+ climb
• 70km, 1,700 D+ climb
• 100km, 2,500 D+ climb
• 162km, 5,000 D+ (incl.

Bib numbers range from €23 to €185 (prices vary according to distance covered). This is the not-to-be-missed ultra-trail event in the Paris region this autumn 2025!