Slovenian Caves & Karst
Postojna, Skocjan and the limestone landscape that named the karst.
The word karst is Slovenian. The limestone plateau between Ljubljana and the coast gave its name to the entire landform, and to every cave system in the world that behaves like it.
Two caves dominate the visitor map and they are not interchangeable. Postojna is the spectacle: an electric train, vast decorated chambers, and the aquarium holding the olm. Skocjan is the one that stays with you – a river canyon inside a mountain, crossed by a bridge 45 metres above the water, and a UNESCO World Heritage Site since 1986.
The comparison below covers both, plus the quieter caves most itineraries skip. Temperatures underground sit around 8 to 12C year-round regardless of the season outside, so bring a layer even in August.
| Cave or site | Best for | Time needed | Access | Nearest base | When to go | Guide |
|---|---|---|---|---|---|---|
| Postojna Cave | First-time visitors, families, scale | 2 hours | Cave train, paved paths | Postojna | Year-round | Read guide |
| Skocjan Caves | Underground canyon, UNESCO listing | 2-3 hours | Steep steps, no train | Divaca | Year-round | Read guide |
| Predjama Castle | Castle built into a cliff face | 1 hour | Short walk, some stairs | Postojna | Apr-Oct | Coming soon |
| Krizna Cave | Underground lakes by boat, small groups | 1-3 hours | Guided boat tour, booking required | Cerknica | May-Oct | Coming soon |
| Vilenica Cave | Europe’s oldest tourist cave | 1 hour | Steps, limited opening | Sezana | Apr-Oct | Coming soon |
| Rakov Skocjan | Natural stone bridges, valley walk | Half day | Easy marked trail | Cerknica | Apr-Oct | Coming soon |
Scroll to see all columns →
What the tour guide mentions in passing
Three things about the underground
Featured
Postojna or Skocjan?
If you only do one, the honest answer depends on what you want. Postojna is easier, bigger and better equipped, and works with young children or limited mobility. Skocjan means several hundred steps and no train, and it is the more extraordinary place.
Latest guides to caves and karst
Skocjan Caves: Slovenia’s UNESCO Underground Canyon, ExplainedSlovenia's most dramatic cave: an on-foot walk through a UNESCO-listed canyon, crossing a bridge suspended 47 metres above the Reka River.
Postojna Cave: Slovenia’s Most-Visited Cave, ExplainedSlovenia's most-visited cave: an easy, partly-by-train tour through vast decorated chambers and the underground olm.Frequently asked questions
Postojna or Skocjan – which should I choose?
Postojna for accessibility, scale and families. Skocjan for the underground canyon and the stronger experience, if you can manage several hundred steps.
Can I visit both caves in one day?
Yes. They are about 30 minutes apart by car and many visitors do both, though it makes for a full day.
Do I need to book cave tours in advance?
For Postojna in summer, yes. Skocjan runs at fixed times and rarely sells out, but check the schedule. Krizna Cave requires booking year-round.
How cold is it inside?
Around 8 to 12C all year, with high humidity. Bring a jacket even in August.
Are the caves suitable for children?
Postojna is, with the train and paved paths. Skocjan involves stairs and exposure on the bridge, which suits older children better.
Can I photograph inside the caves?
Rules vary and change. Skocjan has historically restricted photography in the canyon section; check on arrival rather than assuming.
Newsletter
Don't miss anything new
One new Slovenia guide in your inbox every couple of weeks. No spam, unsubscribe any time.