The stretch of Switzerland everyone reads a book through
Aarau and Olten sit on the Bern–Zürich rail corridor that most Interlaken visitors cross without a second thought, usually asleep or reading, on the way to somewhere with a mountain in the name. That is not entirely unfair. Neither town has a Jungfraujoch or a Chapel Bridge, and if your time in Switzerland is short, you should spend it on the things this site otherwise recommends. But if you have already done Bern, Lucerne and Zürich, or you want a day that is not about altitude, Aarau’s painted old town, Olten’s covered bridge, and two genuinely interesting castles nearby (Lenzburg and Habsburg) make a fair day out — provided you go in with realistic expectations about how much there actually is to see.
This is the canton of Aargau, Switzerland’s fourth most populous and one of its least visited by foreign tourists, sandwiched between Bern, Zürich and Basel. It is flat by Swiss standards, built on the Aare river’s lower reaches, and quietly wealthy from pharmaceutical and engineering industry around Baden. None of that sells postcards. What it does have is a concentration of well-preserved small-town architecture and two of the country’s oldest inhabited castles, both reachable without a car.
Getting there from Interlaken
There is no direct train. From Interlaken Ost, you change in Bern: Interlaken–Bern takes about 52 minutes, and Bern–Aarau a further 30–35 minutes on the InterCity line toward Zürich, giving a realistic door-to-door time of around 1h45. Olten is slightly closer, since some Bern–Zürich services stop there before continuing to Aarau; budget 1h20–1h30. Both towns are on the same line, one stop apart in either direction, so you can genuinely do a loop: Bern, Aarau, Olten, Bern, without backtracking.
A Half Fare Card cuts the fare meaningfully if you are already using one elsewhere in your trip; a standalone Saver Day Pass can also work out cheaper than two one-way tickets if you book it a few days ahead. Neither Aarau nor Olten needs the Swiss Travel Pass’s premium mountain-transport coverage, so do not buy one specifically for this day — see the /guides/swiss-travel-pass-guide/ breakdown if you are still deciding what to buy for the rest of your stay.
If a car is part of your trip, the drive from Interlaken is around 1h30 via the A1 motorway past Bern, and parking in both old towns is metered and limited, which is one more reason the train is the sensible choice here.
Aarau: painted eaves and a walkable old town
Aarau is the capital of Aargau, a town of around 22,000 people whose old town is compact enough to see properly in two to three hours. Its signature feature is the painted timber eaves (“Dachvorsprünge”) along streets like the Graben and Rathausgasse — decorative panels under the roofline, painted in the 18th and 19th centuries with floral and geometric motifs, unique enough in Switzerland that Aarau is sometimes nicknamed the town of painted gables. Walk the length of the Graben slowly and look up; the ground-floor shopfronts are unremarkable, but the upper storeys are where the interest is.
The Rathaus (town hall) and the Stadtkirche (town church, with a clock tower you can climb for a view over the rooftops and the Aare) anchor the old town’s centre. The Kunsthaus Aarau holds a respectable collection of 19th- and 20th-century Swiss art and is worth 45 minutes if you enjoy small regional galleries; it is not a reason to travel here on its own.
A private guided walk is the efficient way to get the history rather than guess at it from plaques — a private walking tour with a local guide covers the painted eaves, the old fortifications, and the town’s role as a short-lived capital of the Helvetic Republic in 1798, in about 90 minutes to two hours depending on how many questions you ask.
Practical note: Aarau’s old town is largely pedestrianised and flat, unlike the hill towns you may have already visited around Lake Thun or Lake Brienz, which makes it an easy, low-effort walking day if your legs need a rest from mountain paths.
Lenzburg Castle: a short detour with a genuine payoff
Lenzburg, a 12-minute regional train ride from Aarau, has one of the oldest continuously inhabited castles in Switzerland, dating to the 11th century and occupied in some form until 1956, when the last private owner sold it to the canton. The castle sits on a hill above the town, a 15-minute walk up from the station with no shuttle, and the climb is unshaded, so factor that in on a hot day.
Inside, the rooms span roughly a thousand years of continuous renovation, which is more interesting than it sounds: you walk from a medieval keep into rooms decorated in 19th-century historicist style by the American family who bought it as a private residence, then back out to ramparts with a genuinely wide view over the Swiss Plateau toward the Jura. Entry runs around CHF 12–15 for adults; check opening days before you go, since the castle typically closes on Mondays and reduces hours in winter.
Families extending the day sometimes combine Lenzburg with onward transport to Europa Park across the German border — a transport and entry package to Europa Park from Lenzburg exists for exactly this, though it is worth being clear-eyed that this turns your Aargau day into a theme-park day in a different country, not an extension of the castle visit. If Europa Park is the actual goal, treat Lenzburg as a stopover on the way rather than the reverse.
Olten: the covered bridge and a railway junction that takes itself seriously
Olten’s old town is smaller and, frankly, less immediately picturesque than Aarau’s, but it has one strong feature: the Alte Brücke, a covered wooden bridge crossing the Aare on stone piers, rebuilt several times since the medieval original and now carrying only pedestrians and cyclists. It is a smaller, quieter cousin of Lucerne’s Kapellbrücke, without the crowds, the flower boxes, or the entry-level tourist-trap prices around it — a fair trade if you have already seen the more famous version.
Olten calls itself, somewhat proudly, the railway junction of Switzerland: it sits at the meeting point of lines toward Bern, Basel, Zürich and Lucerne, and the Swiss national rail company SBB has its operations headquarters here. This is not a sightseeing fact so much as an explanation for why Olten looks the way it does — a working town shaped by rail infrastructure rather than tourism, with a functional rather than manicured old town around the church of St Martin.
Realistically, Olten earns 90 minutes to two hours: cross the covered bridge, walk the small old town core, have lunch, and move on. It is a stop to add to Aarau, not a destination to build a day around by itself.
Habsburg: the castle that named an empire
The genuinely striking stop on this route is Schloss Habsburg, a small hilltop castle near Brugg (itself a short train ride from either Aarau or Olten, and worth its own hour for its own old town and second covered bridge over the Aare). Built around 1020–1030 by Radbot of Klettgau, it gave its name to the House of Habsburg, the dynasty that went on to rule Austria, Spain and the Holy Roman Empire and, at its 19th-century peak, the Austro-Hungarian Empire — an outsized historical footprint for what is, physically, a modest stone keep on a wooded hill.
The castle interior is small and can be seen in 30–40 minutes; a restaurant now occupies part of the complex if you want lunch with the view. The real value is context rather than scale: standing on the exact spot where a regional noble family started a project that ended up running half of Europe, and understanding why so many streets and squares across the former empire, from Vienna to Trieste, still carry the Habsburg name.
Getting there from Brugg station takes about 20 minutes on foot uphill, or a short bus ride in season. A guided option covering Brugg, Habsburg and the wider corner of Aargau in one outing — the six-hour safari through the hidden corners of Aargau — is worth considering if you would rather not plan train connections between three small stations yourself; it is a longer commitment than the rest of this itinerary, so treat it as an alternative to the self-guided version rather than an add-on.
A realistic one-day plan
| Time | Stop | What you do |
|---|---|---|
| Depart Interlaken Ost ~7.15am | — | Change in Bern |
| Arrive Aarau ~9.00am | Aarau | Old town walk, painted eaves, Stadtkirche tower |
| ~11.00am | Lenzburg | Castle visit (12-min train, 15-min walk uphill) |
| ~1.00pm | Olten | Lunch, covered bridge, old town (train via Aarau or direct) |
| ~3.30pm | Brugg / Habsburg | Castle and view, if energy allows |
| Return via Bern | — | Back into Interlaken by early evening |
This is a full, tiring day, closer to nine or ten hours door to door. Dropping Habsburg or Lenzburg brings it down to a more comfortable six or seven hours if you would rather not rush.
What it costs
| Item | Approximate cost (CHF) |
|---|---|
| Return rail, Interlaken–Bern–Aarau/Olten loop | 60–75 (half with Half Fare Card) |
| Lenzburg Castle entry | 12–15 |
| Habsburg Castle entry | 8–10 |
| Lunch in Olten or Aarau | 20–28 |
| Coffee, snacks, incidentals | 10–15 |
| Total per person | 110–145 |
This sits toward the cheaper end compared with a Jungfraujoch or Schilthorn day, which is one honest argument for including Aarau and Olten in a longer stay: it is a lower-cost, lower-altitude day that still delivers real Swiss history, useful if your budget or your legs need a break partway through a trip built around /guides/best-mountain-excursions-from-interlaken/.
When to go
Both towns work in any season, since the appeal is old-town architecture and castle interiors rather than views or hiking. Winter is genuinely fine here, unlike a mountain day that risks being cancelled for wind or cloud — a reasonable fallback if you check /guides/things-to-do-in-interlaken-when-it-rains/ and find your original plan for the day is off. Summer weekends bring more day-trippers into Aarau’s old town, though nothing close to Lucerne or Interlaken’s own crowding. Spring and early autumn are the most comfortable for the uphill walks to Lenzburg and Habsburg.
Is it worth it, compared with the alternatives
Weighed honestly against other day trips from Interlaken, Aarau and Olten rank below Bern, Lucerne and Zürich for a first-time visitor with only one or two spare days — see /guides/day-trips-from-interlaken/ for how those compare directly. Where this trip earns its place is on a second or third visit to the region, or for travellers with a specific interest in castles and medieval history who have already covered the headline stops.
It also works well as a one-way routing rather than a there-and-back: since Aarau and Olten sit directly on the line toward Zürich, and Olten connects on to Basel in well under 40 minutes, you can end the day in either city instead of returning to Interlaken, folding this into a longer /guides/zurich-in-one-day-from-interlaken/ or a Basel-bound itinerary rather than treating it as an isolated loop.
Common questions about visiting Aarau and Olten
Can I visit Aarau and Olten in one day from Interlaken?
Yes, but it is a long day. Both towns sit on the same Bern–Zürich rail corridor, roughly 15 minutes apart by train, so a loop through Bern, Aarau, Olten and back to Interlaken is realistic if you start before 8am and accept that neither stop gets more than two or three hours.
Is Aarau or Olten more worth the detour?
Aarau, on balance. Its painted timber eaves along the Graben and Rathausgasse are a genuine visual set piece with no real equivalent elsewhere in the region, while Olten’s appeal is a single good covered bridge and an old town that is pleasant rather than remarkable.
What is Habsburg Castle and is it worth visiting?
Habsburg Castle is a small 11th-century keep on a hill near Brugg, the original seat of the family that gave its name to the Habsburg dynasty and eventually ruled the Austro-Hungarian Empire. The castle itself is modest inside; the value is standing in the actual birthplace of that name and the view over the Aare valley.
How do I get from Aarau to Lenzburg Castle?
Regional trains run from Aarau to Lenzburg in about 12 minutes, with departures roughly twice an hour. The castle sits on a hill a 15-minute walk above Lenzburg station; there is no direct shuttle, so budget the walk into your schedule.
Do I need a Swiss Travel Pass for this trip?
Not specifically for Aarau and Olten, since neither has a mountain railway or boat premium fare. A Half Fare Card pays for itself on a single Bern–Aarau–Olten–Bern loop if you are already making other rail trips during your stay; otherwise buy point-to-point tickets or a Saver Day Pass.
Is Olten’s covered bridge the same style as Lucerne’s Chapel Bridge?
Same principle, much smaller scale. Olten’s Alte Brücke crosses the Aare on stone piers with a wooden roof, but it carries far less decoration and far fewer tourists than Lucerne’s Kapellbrücke, which is part of its appeal if you have already seen Lucerne.
Can I combine Aarau and Olten with Zürich or Basel in one itinerary?
Yes, and it is arguably the better plan than a return trip to Interlaken the same day. Aarau and Olten both sit on the direct line toward Zürich, and Olten also connects west to Basel in under 40 minutes, so a one-way routing that ends in either city works well if your itinerary already has you moving on toward /destinations/basel/ or /destinations/zurich/.
