Lake Thun | Interlaken

Information

Landmark: Lake Thun
City: Interlaken
Country: Switzerland
Continent: Europe

Lake Thun, Interlaken, Switzerland, Europe

Lake Thun (Thunersee) is an alpine lake in the Bernese Oberland, situated at the western end of the Interlaken isthmus.

Visual Characteristics

The lake is noted for its deep turquoise and deep blue water. It is bordered by steep mountain slopes, including the Niesen ("The Swiss Pyramid") and the Stockhorn range. The shoreline is punctuated by five distinct medieval castles and several historic Romanesque churches.

Location & Access Logistics

Dimensions: Approximately 17.5 km long and 3.5 km wide; maximum depth is 217 meters.

Primary Hubs: Thun (west end) and Interlaken (east end).

Water Transit: CGN/BLS Ferries operate regular scheduled services connecting Interlaken West to Thun, stopping at villages such as Spiez, Merlingen, and Beatenbucht.

Rail: The main railway line between Bern and Interlaken runs along the southern shore, providing direct views of the lake.

Road: The A6/A8 motorway and a northern shore road offer full vehicle access around the perimeter.

Historical & Geographical Origin

Lake Thun was formed after the last ice age. It was originally part of a larger lake (Lake Wendel) that included Lake Brienz; the two were separated by the deposition of the "Bödeli" alluvial plain by the Lütschine and Lombach rivers. The lake acts as a natural reservoir for the Aare river.

Key Highlights & Activities

Cruising: Historic paddle steamers like the DS Blümlisalp operate during the summer months.

St. Beatus Caves: Located on the northern shore, these karst caves feature illuminated stalactites and underground waterfalls.

Castles of Lake Thun: Five castles (Thun, Schadau, Hünegg, Oberhofen, and Spiez) are accessible from the shore.

Water Sports: High-wind conditions near Gunten make it a hub for sailing and windsurfing.

Lido/Strandbad: Public swimming areas are located in Thun, Spiez, and Merlingen.

Infrastructure & Amenities

Connectivity: Consistent 5G coverage across the entire lake surface and surrounding roads.

Accessibility: Most BLS ferries are wheelchair and stroller accessible. Lakefront promenades in Thun and Spiez are flat and paved.

Dining: Extensive lakeside dining options are concentrated in the Spiez bay and the Thun "Mühleplatz" area.

Best Time to Visit

Summer (June–August): For swimming, full ferry schedules, and evening sunset cruises.

Spring/Autumn: For hiking the Panoramaweg, a trail featuring several suspension bridges (like the Sigriswil Bridge) overlooking the lake.

Facts & Legends

A verified fact: Lake Thun is used as a thermal energy source for several local heating projects. A local detail: The "Beatus" legend claims the Irish monk Beatus drove a dragon out of the caves on the northern shore in the 6th century.