Interlaken Lakes: Thun or Brienz, and Where to Swim

Three easy places to swim near Interlaken: Neuhaus on Lake Thun (free area), the Bönigen lido on Lake Brienz and the Burgseeli in Goldswil, a moor lake that can reach 26°C. You may swim anywhere on both big lakes unless a sign forbids it.

The water was a colour that I had only ever seen in toothpaste advertisements. I was twenty years old, standing on the shore of Lake Brienz in mid-June, and I genuinely did not understand how a body of water could be that turquoise without artificial dye.

Three years later, I have stood on the shores of nearly every lake in the Bernese Oberland and I still do not entirely understand it. The science is interesting (we'll get to it). But the experience is something else: a kind of unreality, a feeling that whoever designed this region was showing off.

Around Interlaken there are two big lakes, two famous alpine lakes, one warm little moor lake and three hidden alpine pools that most travelers will never reach. Here is the local guide to all of them.

Why Are the Lakes Around Interlaken That Turquoise Color?

Quick science. The lakes around Interlaken are turquoise because they are fed by glacier melt. The water arrives carrying microscopic particles of ground rock called glacial flour, which scatter blue and green wavelengths of light. The colder and the more glacial the lake, the more dramatic the colour.

Lake Brienz is the most pure-glacier-fed of the major lakes. Its colour stays vivid all summer. Lake Thun receives more mixed water from the Aare and surrounding rivers, so it shifts toward darker blue. The high alpine lakes (Bachalpsee, Oeschinensee) are the closest to the source and turn the deepest emerald in July when the snow has melted but the rock flour is still suspended.

This is also why Lake Brienz stays cold even in August. Swimming in Lake Brienz is for the brave or the briefly insane. Kayaking, sailing and boat tours are for everyone.

Lake Thun: The Bigger Sister

Surface: 48 km² · Depth: up to 217 m · Color: mineral blue, gold at sunset

Lake Thun is the elder of Interlaken's two lakes. It runs west from the town for 17 kilometres, ending at the medieval town of Thun. Its shoreline is dotted with castles (Spiez, Oberhofen, Thun, Schadau, all visible from the water) and the mountains above its south shore hide the vineyards of Spiez.

This is the lake for slow days. The BLS ferries run frequently between villages. You can buy a one-day lake pass and hop on and off, eating in different villages, with no plan beyond be back at Interlaken West by sunset. It is one of the best ways I know to spend a day in the Bernese Oberland.

What Can You Do on Lake Thun?

• Fondue cruise on the BLS fondue boat (dates on bls.ch)

• Visit Spiez : castle, vineyards, lakeside walk, a slow afternoon above the water.

• Stop at Oberhofen Castle : 13th-century stronghold with one of the most photographed lakeside towers in Switzerland.

• Kayak from Faulensee or Spiez : the south shore is calmer and quieter than the north.

• Swim from Strandbad Thun or Strandbad Hilterfingen : the most popular public swim spots in summer.

Best season: May to September. Best time of day: late afternoon for the golden hour over the vineyards.

Lake Brienz: The Quieter Twin

Surface: 30 km² · Depth: up to 260 m · Color: intense turquoise-emerald

Lake Brienz is the other half of Interlaken. Smaller, narrower, deeper, and much more dramatic. Steep cliffs rise straight from the water. The shoreline is largely undeveloped on the south side. Most of the cars on the lake are concentrated on the north shore (which the highway follows), leaving the south for villages, jetties, and walkers.

This is the lake for adventure. The cold keeps the turquoise vivid, and from a kayak seat that colour is all around you. Hightide, the kayak school in Bönigen we work with, takes groups of up to six along the north shore, under sun-warmed cliffs and past small beaches you cannot reach on foot, with Ringgenberg Castle on its hill above the water.

Fun fact: The little funicular that climbs from the Giessbach boat landing to the falls opened in July 1879, the first cable-driven funicular built for tourists and the first railway line to run on a hydraulic system. It was only electrified in 1948.

Kayaking is only one way to spend a day on the water here. Our local guide to outdoor adventures around Interlaken compares the lake activities with hiking, paragliding and canyoning, with honest notes on price and effort.

What Can You Do on Lake Brienz?

• Kayak from Bönigen : about two hours on the water along the north shore, under the cliffs and past hidden beaches, then back across the open lake. Half-day tours are the sweet spot.

• Visit Iseltwald: the village made famous by the Korean drama Crash Landing on You. The jetty scene turned this small lakeside hamlet into a global TikTok destination overnight. Hundreds of fans, mostly from South Korea and Southeast Asia, arrive every morning as soon as the village opens. Access to the jetty costs CHF 5 (checked on 8 October 2026). If you want the photo without the crowd: before 9h or after 16h. Read our guide to the Iseltwald jetty.

• Take the Brienzersee steamship Lötschberg : a paddle steamer from 1914 still in service. The whole ride from Interlaken Ost to Brienz takes 73 minutes on the timetable of 10 October 2026.

• Visit Giessbach Falls : 14 cascades dropping 400 metres directly into the lake. Reachable by ferry plus funicular.

• Brienz village itself : the wood-carving capital of Switzerland, with workshops you can visit and the Brienzer Rothorn steam railway departing from town.

Insider tip: The BLS boats on Lake Brienz run only from 3 April to 6 December 2026 and again from 26 March 2027, so check the calendar before you plan a winter boat ride. A day pass for both lakes costs CHF 83 in second class, or CHF 41.50 with a Half-Fare Travelcard.

Best season: late May to October. Best time: morning kayak (water is calm before noon).

Lake Thun or Lake Brienz: Which One Should You Choose?

The honest answer: it depends on what you are looking for.

Lake Thun is bigger, calmer, and easier to navigate. There are castles on the shore, ferry stops every hour, and the Jungfrau peaks visible from the water on a clear day. It is the lake you take a family to.

Lake Brienz is more intense. The color is more saturated, the cliffs drop directly into the water, and the south shore is almost entirely undeveloped. It is the lake you go to when you want to feel like no one else has found it yet. If you have one day: Lake Brienz in the morning, Lake Thun in the late afternoon.

The light does different things to each one.

Where to Swim: The Best Spots Near Interlaken

The best swimming spots near Interlaken range from the beaches of Lake Thun and Lake Brienz to a small moor lake that most visitors never find. Water temperature varies a lot: Interlaken Tourism gives 17 to 21°C as the summer average for Lake Brienz, and up to 26°C for the Burgseeli.

Lake Thun

The warmest of the two main lakes. Best spots:

• Neuhaus Beach (free, 6 minutes on bus 21 from Interlaken West station, timetable of 15 October 2026): the go-to for a full beach afternoon without driving anywhere.

• Strandbad Hilterfingen: a classic lakeside setup, great for families.

Lake Brienz (17-21°C in summer)

Colder than Lake Thun because of its glacial sources. Still swimmable, but you feel the difference.

• Bönigen (lido, CHF 6 for adults in 2026, village 2km from Interlaken): the most accessible swim on the Brienz side.

• Strandbad Brienz: organized facilities, cleaner entry points.

Burgseeli: the local secret (up to 26°C)

Five minutes from Interlaken, the Burgseeli is a small moor lake, not a glacier-fed one, and Interlaken Tourism puts its water at up to 26°C in summer, which is rare in this region.

It is also my own swim spot. I go often, every summer, and if you ask me for one moment there:

“The summer morning, the flat water and the mist.”

Pierre Vetsch, guide and founder, interview of 8 October 2026

The spot has a jump platform and a Tarzan rope. Entry costs CHF 6 for adults. And it's where locals actually go when they want to swim without the cold shock.

Christine, a waitress at the Burgseeli, has her own warning for swimmers: “There are snakes around the lake!”

Address: Burgseeli, Goldswil, Ringgenberg.

If you're here for the swim, not the scenery, go to Burgseeli first. Save Oeschinensee for the photos.

The Two Alpine Icons: Bachalpsee and Oeschinensee

Bachalpsee: The Mirror Lake

Altitude: 2,265 m · Surface: 0.08 km² · Color: pure alpine emerald, mirror-still on calm days

Bachalpsee is one of the best-known alpine lakes in the Bernese Oberland. It sits above Grindelwald, accessible by a 50-minute easy hike from the First cable car. On a still morning, the lake reflects the entire Schreckhorn-Wetterhorn massif perfectly. The image is so clichéd that travelers refuse to believe it is real until they stand there.

How Do You Get to Bachalpsee?

• Take the Grindelwald-First cable car (check the operating dates on jungfrau.ch).

• Walk the well-marked trail along the ridge for about 50 minutes.

• Best light: between 7 and 9 a.m. before the wind picks up. The mirror effect requires perfect stillness.

• Combine with the Cliff Walk at First and the Mountain Cart descent for a full day.

Bring layers. Even in July, the temperature at 2,265 m is 10°C cooler than in Interlaken.

Oeschinensee: The Most Beautiful Lake in Switzerland (Allegedly)

Altitude: 1,578 m · Surface: 1.1 km² · Color: electric turquoise, surrounded by 3,000-metre cliffs

Oeschinensee sits inside a natural amphitheatre of vertical rock walls above Kandersteg, and its water comes straight from the snowfields of the Blümlisalp massif. The colour is almost cartoonishly turquoise. From Interlaken West, the train to Kandersteg takes 66 to 67 minutes with a change in Spiez (timetable of 15 October 2026). From Kandersteg station, walk or take the bus to the gondola; it climbs to Oeschinen station, and from there a walk of about 30 minutes leads to the lake.

The mistake visitors make with the lakes around Interlaken, in one line:

“Not doing Oeschinensee.”

Pierre Vetsch, guide and founder, interview of 8 October 2026

Important for 2026: the gondola must be booked in advance until 8 November, at oeschinensee.ch. Return fares are CHF 36 (9 May to 14 June and 22 September to 9 November 2026) or CHF 40 (15 June to 21 September 2026), checked on 8 October 2026. The Swiss Travel Pass gives 50% off, not free access, and the Berner Oberland Pass is no longer accepted since January 2026.

First gondola: 8h30. In winter, the gondola runs daily from 5 December 2026 to 7 March 2027, 9 a.m. to 5 p.m.

If Oeschinensee is the main reason for your trip, we wrote a full guide to Oeschinensee with the gondola timetable, the quieter hours and where the best photo spots are around the shore.

Bachalpsee or Oeschinensee: Which Alpine Lake If You Only Have One Day?

Both lakes are worth a full day. But they are different experiences, and the logistics are different enough to matter.

Booking: Bachalpsee requires no advance reservation. Oeschinensee gondola requires booking (summer season, until 8 November 2026) at oeschinensee.ch.

Pierre's take: If you have half a day, Bachalpsee is the better call. The hike is short, the light at 8h is exceptional, and you'll have it mostly to yourself in June or September. If you have a full day and want the most photogenic lake in the Bernese Oberland, Oeschinensee is worth the logistics. Don't try to do both in one day.

The Hidden Ones: Hinterer Geltensee and the Pools Above

Beyond the famous four, the Bernese Oberland holds a network of small alpine pools that most travelers will never see.

Hinterer Geltensee sits high above the valley floor. The hike in is about 4 hours one way. The reward is silence. On most weekdays you have the lake entirely to yourself.

Iffigsee above Lenk is reachable by a 2.5-hour hike. A turquoise pool surrounded by Karst formations. Less famous than Oeschinensee, less crowded, equally photogenic.

Hinterstockensee below the Stockhorn ridge is reachable by an easier 1-hour walk. A small dark lake, very different in mood from the turquoise giants. Worth it for the mood.

I have brought two clients up to Hinterstockensee on private tours. Both times, we had the lake entirely to ourselves. One of them sat down at the edge and did not say anything for about four minutes. That is usually the sign that you have taken someone somewhere real.

These are not for casual visitors. They require fitness, time, and a willingness to walk. They are also some of the most peaceful afternoons in Swiss tourism.

How to Combine the Lakes in One Trip

If you have one day for lakes, choose one lake and one altitude. The Spiez vineyard walk in the morning + a Lake Thun ferry in the afternoon is a perfect combo, easy on the legs and ending with a sunset over the lake.

If you have two days, do Lake Thun on day one (low altitude, vineyards, castles) and Bachalpsee or Oeschinensee on day two (high altitude, alpine mirror lake).

If you have three or more days, mix all four major lakes. Add a kayak afternoon on Lake Brienz, a hike to a hidden alpine lake, and one slow ferry ride to recover.

💡 Insider Tip from Pierre If you have only one morning for an alpine lake and you cannot decide between Bachalpsee and Oeschinensee, go to Bachalpsee. The hike is half as long, the reflection is more reliably mirror-still, and you finish your morning with the entire afternoon free for paragliding or a vineyard walk in Spiez. Oeschinensee deserves a full day, not a rushed half.

FAQ - Lakes Around Interlaken

What is the most beautiful lake near Interlaken?

Subjective. Lake Brienz for the colour and accessibility, Oeschinensee for the alpine drama, Bachalpsee for the mirror reflection. Most locals would pick Lake Brienz at sunset for an everyday answer and Oeschinensee for a once-in-a-trip splurge.

Can you swim in the lakes around Interlaken?

Yes. On Lake Thun and Lake Brienz you may swim anywhere a sign does not forbid it, according to Interlaken Tourism, but the water is cold. Lake Brienz averages 17 to 21°C in summer (cold but doable), and Oeschinensee reaches up to 20°C, according to its operator. The warmest swim nearby is the Burgseeli, up to 26°C.

Can you swim in Lake Brienz?

Yes. Interlaken Tourism says you may swim anywhere on Lake Brienz unless a sign says otherwise, and gives 17 to 21°C as the average water temperature in summer. The Bönigen lido, next to Interlaken, charges CHF 6 for adults in 2026 and keeps a pool at 24°C for anyone who finds the lake too cold.

Can you swim in Lake Thun?

Yes, anywhere a sign does not forbid it, according to Interlaken Tourism. Near town, Neuhaus in Unterseen (Seestrasse 121) has a free bathing area next to a paid lido with toilets, changing rooms and showers.

Is Lake Brienz in Interlaken?

Almost. Interlaken stands on the Bödeli, the flat ground between Lake Brienz and Lake Thun, and the boats to Bönigen and the rest of Lake Brienz leave from Interlaken. The Bönigen lido lies about 100 m from the Bönigen boat stop.

How deep are Lake Thun and Lake Brienz?

Lake Brienz reaches 259 m at its deepest point and Lake Thun 217 m, according to a 2016 Eawag report written for the Canton of Bern; Interlaken Tourism rounds Lake Brienz to 260 m. Below 60 m, the water of both lakes stays between 5 and 6.5°C all year.

Is it safe to swim in Lake Brienz?

Swimming is allowed, and the Swiss Lifesaving Society's six rules are the ones to follow. Its third rule says never jump into the water when you are overheated, because your body needs time to adapt, and its sixth says never swim long distances alone. Its fifth rule keeps air mattresses and swimming aids out of deep water.

Why are the lakes around Interlaken that turquoise color?

Glacier milk gives Lake Brienz its turquoise colour: the Aare and the Lütschine carry fine rock particles from the glaciers into the lake, and the finest ones sink very slowly and scatter the light, according to the Canton of Bern. In winter, when the water is clearest, the lake looks blue with a slight green tint.

Is Iseltwald worth visiting?

Yes. The village itself is small but charming, and the jetty (made famous by the Korean drama Crash Landing on You) is one of the most-shared photo spots in Switzerland. Visit at sunrise to skip the crowds.

Can you visit all the lakes around Interlaken without a car?

Yes. Trains and lake ferries cover Lake Thun and Lake Brienz. Cable cars or cogwheels reach Bachalpsee (via First) and Oeschinensee (via Kandersteg). The hidden alpine pools require longer walks but are also reachable by public transport plus hike.

What is the best time of year to visit the lakes?

Late June to early September for the alpine high-altitude lakes (snow-free, accessible, longest days). Late May to mid-October for the lower lakes (Thun, Brienz). Avoid mid-July to mid-August at Oeschinensee unless you start very early.

Is the water warm enough to swim in summer?

It depends where you go. Lake Brienz averages 17 to 21°C in summer, according to Interlaken Tourism. For the warmest swim near Interlaken, go to the Burgseeli (Goldswil, Ringgenberg): this small moor lake reaches up to 26°C in summer, and entry costs CHF 6 for adults. Oeschinensee reaches up to 20°C, according to its operator. Possible, but not a swim you'll linger in.

Do I need to book the Oeschinensee gondola in advance?

Yes, throughout the summer season and until 8 November 2026, advance booking is mandatory. Without a reservation, you can arrive to find the gondola fully booked for the day. Book at oeschinensee.ch. First departure is at 8h30. If you can't get a slot, the alternative is to hike up from Kandersteg (about 1h30, +450 m elevation gain). Swiss Travel Pass gives 50% off. The Berner Oberland Pass is no longer accepted.

What is the best month to visit the lakes around Interlaken?

June for the alpine lakes: snow is gone, crowds haven't arrived, and the light is long. July-August for maximum water temperature on Lake Thun and Lake Brienz, but expect significantly more people. September is the best overall compromise: water still warm from summer, alpine lakes still accessible, noticeably fewer crowds, and the first hints of autumn colour on the hillsides.

Plan Your Lake Day and Paddle Lake Brienz

Plan your lake days for the morning if you want stillness, and the late afternoon if you want golden light. The middle of the day is for the cogwheel and the cable car.

Back in town between the two lakes, the big meadow in the centre of Interlaken has its own story. Thirty-seven farmers decided long ago that the Höhematte would stay a meadow, which is why you still see the Jungfrau from the middle of town.

If you do one thing on the water, make it Lake Brienz from a kayak. The kayak tour we book with Hightide Kayak School leaves from their base in Bönigen, about 10 minutes from Interlaken Ost on bus 103. You are out for about three hours, around two of them on the water: along the north shore under the cliffs, past small beaches you cannot reach on foot, then back across the open lake with up to 260 metres of water beneath you. Groups of up to six, from CHF 115 per adult, and your guide sends you the photos and videos of your tour for free.

The doubt I hear before people book: “I have never kayaked.” My answer:

“The kayaks are stable, almost nobody falls in.”

Pierre Vetsch, guide and founder, interview of 8 October 2026

No experience needed: your guide shows you the first strokes before you push off, and the group paddles at an easy pace, with breaks. Bring swimwear or quick-dry sports clothes (no cotton) and a towel; on cooler days you get a wetsuit and a splash jacket. The summer tour runs from May to October, and from November the lake has its own winter tour in a drysuit.

Book my kayak tour on Lake Brienz

How we made this: facts and prices checked at the official sources on 8 October 2026, written with AI assistance.

*Written by Pierre Vetsch, founder and head guide at Swiss Local Adventures