Lake Thun

Lake Thun (Thunersee) is one of the largest lakes in the Bernese Oberland, stretching between the town of Thun and Interlaken. This entry covers the lake itself, on whose northern shore the municipality of Sigriswil sits. The lake covers roughly 48 km², runs about 17 to 18 km in length, reaches a depth of around 217 m, and lies near 560 m above sea level.

Where is the lake and what feeds it?

Thunersee sits in the canton of Bern, about 30 km southeast of the Swiss capital. The main inflow is the Aare, which enters from the Interlaken side and leaves again at Thun. The Kander and the Lombach add further water. Thun, known as the gateway to the Bernese Oberland, marks the western end, Interlaken the eastern one, and smaller villages line the shores in between.

What can you see around Thunersee?

Castles define the shoreline. Oberhofen Castle on the northern shore grew around a heavy defensive tower dating from the early 13th century, and its gardens reward a stroll. Spiez Castle crowns a promontory on the southern shore, and the town is known for vineyards on some of the highest-lying vine slopes north of the Alps. In Thun, a castle of its own towers over the old town.

Sigriswil lies higher up, on a terrace above the water. Its viewpoints look out over the lake and the Bernese Alps. The Justistal valley, where a local cheese-sharing festival takes place in autumn, offers hiking trails.

How do you explore the lake?

By boat is easiest. Services link Thun, Spiez, Oberhofen, Interlaken and other landings, so you can hop off at a castle and catch a later sailing. Railways and roads follow the shores, and hiking and cycling routes let you walk or ride the lake in stages. In summer you can swim at the beaches and lidos, though the water stays cool.

When should you visit?

Late spring, summer and early autumn are best, when boats run a full timetable and the mountain views are clearest. In September you may catch the cheese festival in Justistal. Winter sailings are reduced and some attractions close for the season.

Frequently asked questions

How deep is Lake Thun?

The deepest point is about 217 m, and the surface area is about 48 km².

Is Thunersee the same as the town of Thun?

No. Thun is the town at the western end of the lake, while Thunersee is the body of water that reaches all the way to Interlaken.

Which castles are worth visiting on the lake?

Visitors usually pick Oberhofen on the north shore, Spiez on the south shore and the castle in Thun.

How do you get to Sigriswil?

The municipality lies on the northern shore and can be reached by road from Thun. From there, local hiking routes and viewpoints are close by.