TL;DR: A 2-hour audio companion for the boat cruise from Thun to Interlaken across Lake Thun (Thunersee), passing medieval castles, the pyramid of Niesen, the rugged Stockhorn, and the village of Spiez with its fairy-tale lakeside castle. One of the most castle-rich lake cruises in Switzerland, with the Bernese Alps forming a dramatic southern wall.
Cruise Overview
| Route | Thun -- Hilterfingen -- Oberhofen -- Spiez -- Faulensee -- Leissigen -- Darligen -- Interlaken West |
| Duration | ~2 hours (Thun to Interlaken West) |
| Operator | BLS Schifffahrt (BLS Navigation) |
| Vessel | Historic paddle steamer DS Bluemlisalp or modern motor vessel |
| Swiss Travel Pass | Fully covered (free) |
| Best Seat | Upper deck, starboard (right) side from Thun for castle views; port (left) from Spiez onward for Niesen |
| Best Time | Late morning for the best light on the castles and mountains |
Introduction
[Duration: 3 minutes | Departure from Thun pier]
Welcome aboard, and welcome to this ch.tours audio guide for the cruise across Lake Thun -- the Thunersee -- from the medieval city of Thun to the adventure capital of Interlaken.
Lake Thun is 17.5 kilometers long, up to 3.5 kilometers wide, and reaches a maximum depth of 217 meters. It sits at an elevation of 558 meters above sea level, cradled in a valley between the rolling hills of the Swiss Mittelland to the north and the dramatic wall of the Bernese Alps to the south. The lake is fed by the Aare River, which flows in from Interlaken at the eastern end and exits at Thun in the west, continuing its journey north through Bern and eventually joining the Rhine.
What makes Lake Thun unique among Swiss lakes is its extraordinary concentration of castles. Along the northern shore alone, you will pass no fewer than five castles and manor houses within the first 30 minutes of the cruise. These are not ruins -- most are remarkably well preserved, and one of them, Oberhofen Castle, houses a museum that you can visit. The southern shore is no less dramatic: the Niesen, a near-perfect pyramid of a mountain, rises 2,362 meters above sea level, and the town of Spiez boasts a lakeside castle so picturesque it appears on postcards throughout Switzerland.
If you are on the historic paddle steamer Bluemlisalp, you are aboard a vessel with a storied history. The Bluemlisalp was built in 1906, retired in 1971, and nearly scrapped before a citizen's campaign raised funds to restore it. The ship returned to service in 1992 and is now the pride of the BLS fleet. If you are on a motor vessel, the views are equally spectacular, but do make a note to try the paddle steamer on a future visit.
The boat is leaving Thun. Look back toward the city for a moment.
Segment 1: Departing Thun
[Duration: 6 minutes | 0-10 minutes into the journey]
As the boat pulls away from the pier at Thun Bahnhof, look back toward the city. Thun is one of the most underrated towns in Switzerland -- a city of 45,000 that deserves far more attention than it gets.
The most prominent landmark is Schloss Thun -- Thun Castle -- rising above the town on a steep hill. The massive square tower, known as the Donjon, was built in 1190 by Duke Berchtold V of Zahringen, the same dynasty that founded Bern. The tower is an impressive 25 meters tall, with walls up to 4 meters thick, and it now houses a historical museum with collections spanning 4,000 years, from Neolithic artifacts to medieval weapons. The four corner turrets at the top give the castle its distinctive silhouette, visible from far across the lake.
Below the castle, the Obere Hauptgasse -- Thun's main street -- is one of the most unusual shopping streets in Switzerland. The sidewalks run along the rooftops of the lower-level shops, so you walk at the second-story level, with the actual street and shops below you. It is a unique architectural quirk that delights visitors.
As the boat enters the lake proper, the panorama begins to open up. To the south, the wall of the Bernese Alps stretches across the horizon. On a clear day, you can see from the Stockhorn in the west to the Niesen, the Bluemlisalp massif, and, far in the distance, the snow-covered summits of the Jungfrau region. This southern wall of mountains is one of the most dramatic alpine frontages visible from any Swiss lake.
Segment 2: The Castle Shore -- Hilterfingen and Oberhofen
[Duration: 10 minutes | 10-25 minutes into the journey]
The northern shore of Lake Thun between Thun and Oberhofen is sometimes called the Schlossrundfahrt -- the Castle Cruise -- and for good reason. Within the next few minutes, you will pass a remarkable concentration of stately homes and castles.
On the starboard side, the first grand building you see is Schloss Hünegg, a turreted chateau set in parkland above the lakeshore at Hilterfingen. Schloss Hunegg was built in 1861-1863 in the French Renaissance Revival style and today houses a museum of Art Nouveau and Jugendstil interiors, preserved almost exactly as they were in 1900. The park grounds slope down to the lake and are open to the public.
Moments later, still on the starboard side, the village of Oberhofen comes into view, and with it, one of the most photographed castles in Switzerland. Schloss Oberhofen sits directly on the lakeshore, its medieval tower reflected in the water, its gardens spilling down to a small jetty. The castle dates to the 13th century and has been modified repeatedly over the centuries, creating an eclectic mix of medieval, Baroque, and 19th-century architecture. Inside is a museum of furnished period rooms spanning from the 15th to the 19th century. The gardens are exquisite -- formal parterres, exotic trees, and a Turkish smoking room in the park pavilion that is one of the most unexpected interiors in the country. If you have time on another day, Oberhofen Castle is well worth a visit. Entry is approximately CHF 10.
Behind the castles, the Sigriswil ridge rises to moderate heights, with scattered farms and forests. This is the Berner Oberland at its most pastoral -- green, orderly, and quietly prosperous. The northern shore of Lake Thun has been a favored residential area for centuries, and the quality of the light, the south-facing exposure, and the mountain panorama make it easy to see why.
On the port side, across the lake, the terrain is already steeper and more alpine. The Sigriswilergrat, a dramatic ridge walk accessible by cable car from Sigriswil, offers one of the best viewpoints over the lake.
Segment 3: Spiez
[Duration: 10 minutes | 25-45 minutes into the journey]
The steamer is now crossing toward the southern shore, and the town ahead of you is Spiez -- widely regarded as one of the most beautifully situated towns in Switzerland.
As the boat approaches the Spiez pier, the view is postcard-perfect. The Schloss Spiez -- Spiez Castle -- stands on a low promontory jutting into the lake, its Romanesque church tower and medieval walls reflected in the water. Behind and above the castle, the town rises in tiers of vineyards -- yes, vineyards, at this latitude and elevation. The Spiez vineyards are among the highest commercial vineyards in Europe, producing a light Pinot Noir and a crisp Muller-Thurgau that you can taste at the castle wine shop. The combination of lake, castle, vineyards, and the snowy mountains behind is almost absurdly picturesque.
Spiez Castle itself dates to the 10th century. The early medieval tower is one of the oldest surviving structures in the Bernese Oberland. The castle was the seat of the Barons of Strattligen, then passed to the Bubenberg family -- the same family that produced Adrian von Bubenberg, the hero of the Battle of Murten in 1476. Today the castle is a museum, open from April to October, with beautifully preserved rooms and a small exhibition on the castle's history. Entry is approximately CHF 10.
Spiez is also an important railway junction. The Lotschberg railway line, which connects Bern to the Valais via the Lotschberg Tunnel, passes through Spiez station. If you are heading to Zermatt, Brig, or the Rhone Valley, you will likely change trains here.
Now look to the port side as the boat leaves Spiez. The mountain that dominates the view to the south is the Niesen.
Segment 4: The Niesen
[Duration: 6 minutes | 45-55 minutes into the journey]
The Niesen. At 2,362 meters, it is not the highest peak in the region, but it may be the most distinctive. The Niesen is a near-perfect pyramid -- a triangular peak so symmetrical it looks almost artificial. Paul Klee, the Swiss-born artist who grew up in Bern, painted the Niesen repeatedly, and its geometric form has made it an icon of the Bernese Oberland.
The Niesen is accessible by funicular from Mulenen, near the southern shore of the lake. The Niesenbahn, built in 1910, climbs 1,643 meters over a distance of 3.5 kilometers -- one of the longest and steepest funicular rides in Europe. The summit station sits just below the peak, and from the top, the 360-degree panorama is extraordinary: Lake Thun and Lake Brienz below, the Jungfrau, Monch, and Eiger to the south, and on a clear day, the Swiss Mittelland rolling north to the Jura and, very faintly, the Black Forest beyond. The round trip costs approximately CHF 64, or CHF 32 with the Swiss Travel Pass (50 percent discount).
One peculiar Niesen tradition: every June, the Niesen Treppenlauf takes place -- a staircase race up the 11,674 steps of the service staircase alongside the funicular track. It is the longest staircase race in the world, and competitors complete it in as little as 60 minutes. The staircase is normally closed to the public, but the race has become a cult event in Swiss endurance sports.
Segment 5: The Stockhorn and the Southern Shore
[Duration: 6 minutes | 55-65 minutes into the journey]
Looking west from the Niesen, the rugged massif visible on the port side is the Stockhorn range, anchored by the Stockhorn peak at 2,190 meters. The Stockhorn is the northernmost significant peak of the Bernese Alps on this side of the lake, and its craggy summit is accessible by cable car from Erlenbach im Simmental. The Stockhorn cable car is one of the steeper rides in the region, and the summit terrace offers vertiginous views down to the lake and across to the entire Bernese Oberland chain.
The Stockhorn is particularly popular with paragliders, who launch from near the summit and soar above the lake on thermals. If you look up on a clear day, you will almost certainly see colorful paraglider canopies circling above the southern shore.
Between the Stockhorn and the Niesen, the Simmental valley opens southward into the Bernese Alps. This valley is the traditional home of the Simmental cattle breed -- the distinctive red-and-white cows that are one of Switzerland's most iconic images. The Simmental breed originated in the valley behind you and is now one of the most widely distributed cattle breeds in the world.
Segment 6: Faulensee to Leissigen
[Duration: 8 minutes | 65-80 minutes into the journey]
The boat is now cruising along the southern shore toward the eastern end of the lake. The villages along this stretch -- Faulensee, Leissigen, Darligen -- are small, quiet communities that see far fewer tourists than Interlaken or Spiez, but they offer some of the most authentic Oberland scenery on the lake.
On the starboard side, the northern shore is now steeper and more forested. The Beatenberg ridge rises above, and hidden in the cliff face is the entrance to the St. Beatus Caves -- the Beatushohlen -- a network of stalactite caves that extends over a kilometer into the mountain. According to legend, the caves were once the lair of a dragon, which was driven out by the Irish monk St. Beatus in the 6th century. The caves are open for guided tours from April to October, and the entrance, with a waterfall cascading past the cave mouth, is one of the most atmospheric sights on the lake.
As the eastern end of the lake comes into view, the panorama ahead of you opens up to reveal some of the most famous mountains in the world. Directly south, the pointed peak partially visible through the gap in the valley is the Jungfrau, at 4,158 meters -- one of the great summits of the Alps. To its left, the rounded dome of the Monch (4,107 m) and the dark, north-facing wall of the Eiger (3,967 m) may be visible depending on conditions. These three peaks -- Eiger, Monch, and Jungfrau -- form the signature skyline of the Bernese Oberland and are a UNESCO World Heritage site.
Segment 7: Approaching Interlaken
[Duration: 8 minutes | 80-100 minutes into the journey]
The lake is beginning to narrow as you approach its eastern end. The town of Darligen marks the point where the Aare River enters the lake, and from here, the landscape flattens into the alluvial plain that connects Lake Thun to Lake Brienz -- the strip of land on which Interlaken is built.
Interlaken -- the name literally means "between the lakes" -- sits on this narrow plain between Lake Thun and Lake Brienz. The town has been a center of Swiss tourism since the early 19th century, when English travelers began arriving to admire the mountain scenery. The Hohematte -- the large green meadow in the center of town -- was deliberately kept undeveloped so that the view of the Jungfrau from the grand hotels would remain unobstructed. That view is still intact today, and on a clear morning, standing on the Hohematte with the Jungfrau shining white above the valley, you understand why Interlaken became world-famous.
The boat will dock at Interlaken West, the pier closest to the western end of town. From here, it is a short walk to Interlaken West station, where you can catch trains toward Bern, Lucerne, or the Jungfrau region. If you want to continue by boat to Lake Brienz, you will need to take a short bus or train ride to Interlaken Ost station and the Lake Brienz pier -- the two lakes are not directly connected by boat.
On the starboard side, as the boat makes its final approach, look for the Harder Kulm -- the 1,322-meter viewpoint directly above Interlaken, accessible by funicular. The viewing platform at the top, called the Two Lakes Bridge, offers a panoramic view of both Lake Thun and Lake Brienz simultaneously, with the Jungfrau massif behind. It is one of the finest viewpoints in the Bernese Oberland.
Arrival and Closing
[Duration: 3 minutes]
As the boat comes alongside the pier at Interlaken West, your cruise across Lake Thun is complete. Over the past two hours, you have traveled 17.5 kilometers through a landscape of castles, vineyards, pyramidal mountains, and alpine grandeur.
Lake Thun occupies a special place among Swiss lakes. It lacks the raw drama of Lake Lucerne or the Mediterranean flair of Lake Lugano, but it compensates with a quiet, layered beauty -- medieval castles reflected in still water, vineyards climbing impossible slopes, and the Bernese Alps forming a wall of white along the southern horizon. It is a lake that reveals itself slowly, rewarding patience and attention.
If you are continuing to explore the Bernese Oberland, ch.tours offers audio guides for Lake Brienz, the Jungfrau region, and the GoldenPass Express from Interlaken to Montreux. Spiez is also the gateway to the Lotschberg route toward the Valais and Zermatt.
For a truly complete experience, consider taking the boat in one direction and the train in the other -- the BLS railway runs along the northern shore of Lake Thun, and the views from the train are a perfect complement to the views from the water.
Thank you for joining this ch.tours Lake Thun cruise. Enjoy the rest of your time in the Bernese Oberland.
Source: ch.tours | Audio Guide Script | Last updated: March 2026 | Data from BLS Schifffahrt (bls.ch), MySwitzerland.com, SBB (sbb.ch), Swisstopo, Schloss Oberhofen, Schloss Spiez, Niesenbahn