Routes

Planner

Features

Updates

App

Login or Signup

Get the App

Login or Signup

Login or Signup

Routes
Hiking trails & Routes
France
New Aquitaine
Oloron-Sainte-Marie
Laruns

Tour of the Ayous Lakes

Hard

4.8

(251)

2,421

hikers

Tour of the Ayous Lakes

05:29

15.8km

770m

Hiking

This difficult 9.8-mile hike in the Pyrenees offers stunning views of Pic du Midi d'Ossau and passes several beautiful glacial lakes.

Last updated: February 26, 2026

Tips

Your route passes through protected areas

Please check local regulations for:

Parc national des Pyrénées (cœur)

Waypoints

A

Start point

Parking

Get Directions

1

2.76 km

Ossau Valley

Highlight • Gorge

This valley follows the course of the Gave de Bious and offers a superb deep and clear panorama. A green expanse in contrast with the passes, peaks and rocky massifs …

Translated by Google •

Tip by

2

4.88 km

Lac Roumassot

Highlight • Lake

Lake Roumassot is the lowest of the Ayous lakes. This natural lake of glacial origin is located at an altitude of 1,845 meters and serves as a summer pasture for …

Translated by Google •

Tip by

3

5.79 km

The Ayous lakes form a group of six lakes: Castérau, Miey, Gentau, Bersau, Paradis and Roumassot.

Arranged in stairs, they form a magnificent amphitheater to land and admire the Pic …

Translated by Google •

Tip by

4

6.32 km

Refuge d'Ayous

Highlight • Mountain Hut

The Ayous refuge is open from the end of May to the beginning of October. For the precise dates, which change from one year to the next, you can go …

Translated by Google •

Tip by

5

7.37 km

Lac Bersau

Highlight (Segment) • Lake

Lake Bersau is located 2,080 meters above sea level, at the foot of Pic Casterau. It is one of the six lakes of Ayous which mark out the paths of …

Translated by Google •

Tip by

6

9.00 km

Lac Castérau

Highlight • Lake

Lake Castérau is located on the edge of the road to Saint-Jacques-de-Compostelle. It is one of the six lakes of Ayous. Located at the foot of the Castérau peak (2,227 …

Translated by Google •

Tip by

B

15.8 km

End point

Parking

Loading

Way Types & Surfaces

Way Types

6.93 km

5.29 km

2.39 km

1.15 km

Surfaces

10.3 km

3.76 km

1.15 km

599 m

Sign up to see more specific route details

Sign up for free

Elevation

Elevation

Nothing selected – click and drag below to see the stats for a specific part of the route.

Sign up to see more specific route details

Sign up for free

Weather

Powered by Foreca

Thursday 7 May

8°C

3°C

-- %

Additional weather tips

Max wind speed: -- km/h

to get more detailed weather forecasts along your route

This route was planned by komoot.

Save

Edit route

Download GPX

Move start point

Print

Share

Embed on a website

Report an Issue

Frequently Asked Questions

How long does it take to hike the Great hike of the lakes of Roumassot, Bersau and Castérau?

This challenging hike typically takes around 5 hours and 30 minutes to complete. However, given its difficulty and significant elevation gain, it's wise to allow extra time for breaks, enjoying the views, and navigating the varied terrain.

What is the difficulty level of this hike?

This route is considered difficult, demanding very good fitness and sure-footedness. It involves a significant elevation gain of about 775 meters over approximately 15.8 kilometers, with varied and sometimes steep terrain. It corresponds to a SAC (Swiss Alpine Club) rating of 4-6.

What kind of terrain can I expect on the trail?

The terrain is quite varied. You'll encounter a mix of unpaved paths, natural surfaces, and some short asphalt sections. Expect steep and winding parts, especially through forests and along a picturesque waterfall. The descent from Lac Castérau is particularly noted for being steep, winding, and rocky. At higher altitudes, such as around Lac Bersau, you might find snow and melting ice even in late spring.

What are the main highlights and viewpoints along the route?

The hike offers a superb panorama of the Ossau Valley and consistent, incredible views of the majestic Pic du Midi d'Ossau. You'll pass several stunning glacial lakes, including Lac Roumassot, Lac Miey, Lac Gentau, Lac Bersau, and Lac Castérau, which are arranged like stairs. Lac Gentau is considered one of the most beautiful, and Lac Castérau offers striking reflections of the Pic du Midi d'Ossau.

What is the best time of year to hike this trail?

The ideal time to hike this trail is generally from late spring to early autumn. The Refuge d'Ayous is typically open from late May to early October, which aligns with the best conditions. Be aware that snow and melting ice can still be present at higher altitudes, particularly around Lac Bersau, even in late spring.

Does the trail intersect with other well-known paths?

Yes, portions of this route align with the GR10, a renowned long-distance hiking path that traverses the French Pyrenees. It also passes through sections of the Voie d'Ossau, La traversée des Pyrénées - sec.7, and the Sentier du Tour des Lacs d'Ayous PNP.

Is the Great hike of the lakes of Roumassot, Bersau and Castérau dog-friendly?

As this trail is located within the Pyrenees National Park, there are generally restrictions on dogs. Dogs are typically not allowed, even on a leash, in the central zone of the National Park to protect wildlife. Please check the latest regulations from the Pyrenees National Park authority before planning your visit with a dog.

Are there any facilities or water sources available on the trail?

Yes, near Lac Gentau, you'll find the Refuge d'Ayous. This refuge provides water and restroom facilities and is usually open from late May to early October. It's always recommended to carry sufficient water for your hike, especially outside of the refuge's operating season.

Do I need a permit or is there an entrance fee for this hike?

The trail is located within the Pyrenees National Park. While there isn't typically an entrance fee for hiking in the park, certain regulations apply, especially regarding camping, fires, and dogs. It's always a good idea to check the official Pyrenees National Park website for any specific rules or temporary restrictions before your visit.

Where can I park to access the trailhead?

The most common starting point for hikes in this area, including routes to the Ayous lakes, is often from the Bious-Artigues car park. From there, various paths lead into the network of trails. It's advisable to arrive early, especially during peak season, as parking can fill up quickly.

Is it possible to camp along the trail?

Wild camping is generally regulated within the Pyrenees National Park. However, near Lac Gentau, there is a wide esplanade where bivouacking is permitted under specific conditions, usually between 7 PM and 9 AM, and at least an hour's walk from road access. Always respect park rules and leave no trace.

Nearby routes

Hard

4.8

2,421

Tour of the Ayous Lakes

05:29h

15.8km

770m

Trail Reviews

Carla
August 12, 2023, Grande randonnée des lacs de Roumassot, Bersau et Castérau

It is a beautiful route, but with some difficult sections. If you like nature, walking among animals and waterfalls, and above all, resting in each lake, you will love this route. fitness required

Translated by Google

What to say ! Exceptional… nature in all its splendor. The presence of man is limited and it shows! The hike goes uphill, but not particularly difficult. There is a charge for parking: €3 at the bottom, €6.5 at the top. I highly recommend the upper parking lot. At the end of the hike, it's nice and a small cabin offers pancakes and drinks right next to it and it's good! I also advise arriving very early, 7:30 a.m. / 8 a.m. max, after too many people and the weather changes very quickly! See the “Road trip in the French Pyrenees” collection to discover other hikes: https://www.komoot.com/fr-fr/collection/2378221/-road-trip-dans-les-pyrenees-francaises

Translated by Google

The tour of the Ayous lakes: Departure: Lac de Bious-Artigues, Laruns (1419 m - 19 km from Laruns) - View of the Pic du Midi, the Roumassot (1846 m), Miey (1912 m), Gentau (1947 m), Ayous (1916 m), Bersau (2103 m) lakes. Altitude: 2104 m - Elevation: 728 m - Distance: 15 km - Duration: 4h30.

Translated by Google

A superb day of hiking. We did it in the opposite direction to the recommended route. We left early from the highest parking lot (€8).

Translated by Google
Jp 64300
August 20, 2022, Randonnée

With beautiful weather, the hike is all the more pleasant. Arriving early makes parking easier.

Translated by Google
Explore
RoutesRoute plannerFeaturesHikesMTB TrailsRoad cycling routesBikepackingSitemap
Download the app
Follow Us on Socials

© komoot GmbH

Privacy Policy