Postojna is Slovenia's great show cave — 24 km of galleries, the world's first cave railway running since 1872, and Predjama, the world's largest cave castle, a short drive away. You reach it on a guided day trip from Ljubljana, Trieste or Koper, often paired with Lake Bled or the coast. Every route, one page — from A$80.
Prices shown are indicative "from" rates in AUD and are confirmed at checkout on GetYourGuide. Availability and exact inclusions vary by date.
Everything you need to plan the trip — the cave, the castle, and the karst at the heart of Slovenia.
Postojna Cave (Postojnska jama) is one of the world's largest karst show caves, with a mapped system running to around 24 kilometres. What makes it unique among show caves is the way you enter: a double-track railway — the world's first cave train, running since 1872 (hand-pushed at first, electrified in the 1920s) — today an electric train carries visitors roughly 3.7 km into the mountain in a matter of minutes, clattering through illuminated galleries before you disembark for the guided walking section. On foot you cover a further 1.5 km or so of level, paved pathway past enormous chambers, delicate dripstone curtains, and the cave's signature formation: the Brilliant, a pure-white, 5-metre stalagmite that has become the symbol of the cave. The full visit, train included, runs about 1 hour 30 minutes, at a constant 10°C — bring a light jacket even in summer.
Near the end of the walking route, a vivarium introduces the cave's most famous inhabitant: the olm (Proteus anguinus), a blind, pale amphibian found only in the karst caves of the Dinaric Alps. Locals nicknamed it the "human fish" for its skin tone, and folklore cast it as a baby dragon that had slipped down from an underground lair after floods — a story that persisted for centuries before naturalists identified it as a cave salamander. Olms can live for decades and survive years without food, an adaptation to the near-total absence of nutrients deep underground. Seeing one in the vivarium is a highlight for most visitors, especially kids.
About 10 km from Postojna Cave, Predjama Castle is built directly into the mouth of a 123-metre cliff-face cave, making it the largest cave castle on Earth. Its most famous resident, the robber baron Erazem of Predjama, reportedly used a secret passage through the cave system behind the castle to keep himself supplied during a year-long siege in the 1480s. The castle and cave visits pair naturally — most tours on this page combine both in a single day, since they're only a short drive apart and take a similar amount of time to explore.
Slovenia has two headline show caves, both in the karst region south-west of Ljubljana, and they suit different travellers. Postojna is the more accessible experience — the cave train does the heavy lifting, the walking route is level and well-lit, and it pairs effortlessly with Predjama Castle, making it the easier choice for families or a tight schedule. Škocjan Caves, a UNESCO World Heritage Site about 30 minutes further south, is the wilder sibling — a colossal underground canyon crossed on foot via high bridges above a roaring underground river, with no train to soften the scale of it. If you have the time, some visitors do both on the same trip. For the Škocjan ladder, see our sibling guide, Škocjan Cave Tours.
Postojna Cave is open daily, year-round, with more frequent guided-tour departures (and longer hours) through the summer high season. Times shift by season, so treat the table below as a guide and confirm your exact date when you book — every pre-booked tour on this page carries a timed or flexible slot.
| Season | Typical daily hours |
|---|---|
| June–September (peak) | 9:00am – 6:00pm, tours roughly hourly |
| April–May, October | 10:00am – 4:00pm, tours every 1–2 hours |
| November–March | 10:00am – 1:00pm & 2:00pm – 4:00pm, fixed departures |
Hours per official Postojnska jama information; always verify the specific date at checkout.
The honest buying advice a checkout page won't give you — matched to who you are:
The small-group Cave & Predjama tour from Ljubljana (from A$80) covers the essentials in about 6 hours without the frills.
The top-pick Cave & Predjama Castle combo (from A$186) with hotel pickup — it's the most complete, least-planning-required option.
A Piran or Trieste-departure tour (from A$178) — cave, castle and a slice of the Adriatic in one day.
A Lake Bled + Postojna combo (from A$145–275) — the two biggest day-trip draws from Ljubljana, done together.
The cave-train section is seated and requires no walking, but the guided walking portion covers gentle slopes and some steps on paved paths — it is not fully wheelchair-accessible throughout, so travellers with mobility needs should check with the operator before booking. The cave stays a constant 10°C, so bring a jacket regardless of the season outside. Summer weekends are the busiest; a morning departure generally means smaller groups. Photography is welcome without flash, and comfortable, closed-toe shoes are recommended for the walking sections.
About 30 minutes further south, Škocjan Caves — a UNESCO World Heritage Site — swap the cave train for high bridges over a thundering underground canyon. See the full tour ladder for the more dramatic sibling.
Postojna Cave Tours is an independent travel guide run by a small team of travel enthusiasts. We are not a tour operator and are not affiliated with Postojnska jama d.d. — we research every Postojna Cave tour and day trip bookable from Ljubljana, Trieste, Koper and Bled, organise them into one clear ladder, and link you to book directly and securely on GetYourGuide.
How we choose: we list only real, currently-bookable tours from operators with genuine verified reviews on GetYourGuide, and we re-check prices, availability and inclusions regularly. When we earn a commission it is paid by the operator, never by you — it costs you nothing extra and never changes which tours we recommend.
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Photography via Wikimedia Commons, used editorially: © Kévin Veau and © Beyond silence (public domain); © Frerk Meyer (CC BY-SA 2.0), © Keith Roper (CC BY 2.0) and © Dragan Kikovic (CC BY-SA 4.0). Postojna Cave Tours is an independent guide; no affiliation with or endorsement by Postojnska jama d.d. is implied.
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We map the full ladder — $80 small-group day trip to the grand Lake Bled combo — so you pick the right route in seconds.
The questions Postojna-bound travellers ask most.
