Caumasee

Caumasee (Romansh: Lag la Cauma) is a small forest lake at Flims in the Swiss canton of Graubünden, and one of the most popular swimming spots in the Flims Laax Falera region. It covers just over 10 hectares and sits a short distance from the village centre.

How did the lake form?

The lake lies on the debris of the Flims rockslide, a huge mountain collapse dated to roughly 9,500 years ago that buried the Rhine valley. Several lakes sit on these deposits. Caumasee has no stream flowing in or out. Its water seeps in from underground sources moving through the broken rock.

Why does the water level change so much?

Because groundwater feeds it, the level swings by about 4 to 5 metres over the year. It is lowest around the end of April, before snowmelt in the mountains picks up. Graubünden has approved a scheme to steady the level by channelling water in from the Platt Alva stream. An ETH Zürich expert judged the plan suitable and advised monitoring turbidity, temperature and phosphate sources in the catchment.

Can you swim here?

Yes, there is a managed lake bath. The lake is shallow and holds little water, so it warms faster than most lakes nearby. In summer expect 17 to 24 degrees C, with about 21 degrees C as a typical figure in hot weather. The water shows a turquoise tint against a backdrop of conifers.

What are the prices and opening times?

For the 2026 season (16 May to 30 August) tickets cost CHF 18 for adults and CHF 9 for children aged 6 to 17, sold through the Inside Laax app. Lifeguards are on duty daily from 8:30 to 17:00. Outside those hours the area can be used free of charge but without supervision. A public section needs no ticket. Dogs are not allowed in the bathing area.

When should you go?

July and August bring the warmest water. On summer weekends the lake gets crowded, so arrive in the morning. In spring the level can be low and the scenery looks quite different from midsummer. Buying a ticket in advance in the app saves time at the entrance.

How do you get there?

The lake is near the Waldhaus area of Flims. From the village you can walk through the forest or take local transport. Coordinates are about 46.820 N, 9.296 E. Walking routes continue across the rockslide terrain from the shore.

Frequently asked questions

Does Caumasee have an inlet or outlet?

No. Underground water feeds it, and the level follows the season and snowmelt.

How much is entry in 2026?

Adults pay CHF 18, children aged 6 to 17 pay CHF 9. Tickets are sold through the Inside Laax app.

Are dogs allowed?

Not in the bathing area.

How warm is the water?

Usually 17 to 24 degrees C, around 21 degrees C on average in midsummer.