Postojna Cave: a subterranean train ride into another world
The chill hits you the moment you step inside the tunnel. It holds steady at 10°C year-round, summer and winter alike. Then the train jolts forward, picks up speed, and plunges you into a realm where time is measured in millions of years. Towering white stalactites brush past the cars, and cathedral-sized chambers loom out of the shadows. Welcome to the largest tourist cave in Europe.
Why visit Postojna Cave?
This 24 km underground network was carved by the Pivka River over two million years. Discovered in the 13th century, it has welcomed visitors since 1819 and hosted more than 39 million people to date. Slovenia features 16,000 karst caves, but this one remains the most spectacular for its sheer scale and accessibility.
It is also the only cave in the world equipped with a double-track railway. Opened in 1872, this subterranean line popularized cave tourism long before electricity reached the depths. The current train cars are modern, but the thrill remains entirely unchanged.
The tour experience
The train ride
The visit starts with 3.7 km of track covered in 10 minutes. The train plunges into illuminated galleries, weaving between giant mineral formations and crossing astonishingly vast chambers. Keep your head down and stay seated unless you want a close encounter with low-hanging stalactites.
The underground walk
After the train ride, a guide takes over for 1.5 km of walking along a paved path. The route stops at the Concert Hall, which can hold 10,000 people, before pausing in front of the Brilliant, a five-meter white stalagmite that has become the symbol of the caves. Photography is permitted without flash.
Friendly tip: Arrive 30 minutes before the time printed on your ticket. Boarding starts 15 minutes before departure, and latecomers have to wait for the next tour.
The olm, the baby dragon of the depths
At the end of the tour, the Vivarium showcases the most famous resident of the caves: the olm, nicknamed the human fish for its translucent pink skin. This blind amphibian adapts to total darkness and can survive for a decade without food. Slovenians view it as the offspring of the dragons that legend says once inhabited these depths.
What to know before you go
The constant 10°C temperature means you need a jacket, even in the middle of summer. The ground is damp in places, so pack sturdy closed-toe shoes with good grip. The visit lasts an hour and a half, and no early exits are possible. The route is accessible to strollers and visitors with reduced mobility, who can choose to remain on the train for the entire experience.
The Predjama Castle, built into a cliff 10 km from the caves, makes an easy pairing for the same day. A combination ticket cuts down the total cost.
Opening hours
Low season: 3 departures per day.
High season: up to 12 departures per day.
Plan to arrive 30 minutes before your scheduled departure.
*Information subject to change
I really loved visiting these caves. The entrance fee is inexpensive, and the tour lasts almost two hours. Part of it is done on a little train, then you explore the rest of the caves on foot. Remember to dress warmly because it is pretty chilly inside, and wear good shoes.