Postojna, the small Slovenian town hiding a world beneath its streets
Electric lighting arrived here in 1883, fifteen years before Ljubljana itself. Not on the surface, but 400 feet underground, deep inside a cave that tourists had already been visiting for over sixty years. That single fact captures the essence of Postojna: a modest town of 10,000 residents sitting on a karst plateau, famous worldwide purely because of what happens underground.
Postojna: a stopover, not a destination
Let's be honest. The town itself does not warrant more than half a day. Its downtown consists of a single square, a baroque church, and a few cafes where locals play cards in the afternoon. Yet nobody comes here for the village square. The caves and Predjama Castle draw over a million visitors every year, making this the top attraction in Slovenia.
This spot works well for families, geology enthusiasts, and anyone looking to break up a standard Slovenia itinerary. Travelers seeking picturesque charm or a late night scene will likely feel let down. Postojna functions as an efficient base camp, and nothing more.
Anticipating costs
Cave admission runs high for the region: figure on $38* for just the cave, $53* to include Predjama Castle, plus $6.80* for parking. A decent hotel room costs between $68 and $113*, while a restaurant meal runs $17 to $29*. A typical daily budget for two people lands around $169 to $230*.
Underground: the Postojna Caves
The underground network stretches across 24 kilometers (nearly 15 miles). Guided tours cover about three miles, with 2.3 miles of that covered aboard an open air electric train. This railway, opened in 1872, was the first underground train in the world. Riding the open cars past giant stalactites remains the main highlight.
The hour-long walking portion that follows passes through the Concert Hall, which can hold 10,000 people, and stops in front of the Brilliant, a five-meter-tall white stalagmite that serves as the site's symbol. The humidity hovers at 95 percent, and the temperature stays locked at 50°F year-round. Bring a jacket, even in mid-summer.
Friendly tip: book the very first tour of the morning to beat the tour groups. During peak season, entry lines can stretch past an hour.
On the cliffside: Predjama Castle
Six miles from the caves, a white fortress emerges directly from a 400-foot rock face. The Guinness World Records recognizes it as the largest cave castle in the world. Built in the 13th century, it gained fame through the robber baron Erazem Lueger, who withstood a year-long imperial siege here by using a secret tunnel that connected the fortress to the valley below.
The interior displays an armory, a chapel, and a torture chamber. A free smartphone audioguide tells the history. Allow an hour for the visit. The cave directly beneath the castle, the second longest in Slovenia, only opens from June to August to protect the resident bats.
The surroundings: getting off the beaten path
Seven miles north, the Planina Cave is the country's largest water cave. Less developed than Postojna, it delivers a wilder experience. The Pivka Military History Park, set inside former military barracks, displays World War II tanks, aircraft, and submarines. Finally, the romantic and baroque ruins of Haasberg Castle make a worthwhile detour for photography fans.
The UNESCO-listed Škocjan Caves sit 19 miles away. Less commercialized and more dramatic in scale, they complement any trip through the karst region.
Where to eat and drink in Postojna?
The culinary scene is modest but solid. Restaurant and Pizzeria Minutka, right in the center, serves standout parmigiana and gnocchi. Locals also recommend Gostilna Ob Kaminu, set beside a lake in a spruce forest, for traditional Slovenian dishes.
Must-try items include jota, a hearty bean and sauerkraut stew native to the karst region, and štruklji, rolled pastries stuffed with walnuts or cottage cheese. Proteus, a downtown restaurant, pours local wines sourced from five Slovenian wine regions.
Where to stay in Postojna and nearby?
The Hotel Jama, completely renovated in 2016, sits just 300 feet from the cave entrance. It is ideal for anyone wanting to be first in line in the morning. Hotel Kras offers views of the Nanos plateau and better value. For tight budgets, the Postojna Cave Rooms & Apartments Proteus offer practical apartments a ten-minute walk from the caves.
Camping Pivka Jama, located near another cave entrance, accommodates tents and RVs with full hookups. It is a practical, budget-friendly choice for roadtrippers.
How to get to and around Postojna?
From Ljubljana, expect a 45-minute drive down the A1 highway, taking exit 41. A highway vignette is mandatory, costing $18* for 7 days. Trains connect Ljubljana to Postojna in an hour for $6.80*, though the station sits a mile and a quarter from the caves. Buses are more convenient, dropping you directly in front of the park entrance.
From Trieste, Italy, the drive takes 40 minutes. From Koper on the Slovenian coast, figure on 40 minutes as well. A shuttle bus links the caves to Predjama Castle during peak season for $2.30* round-trip. Off-season, a taxi runs about $17*.
When to go?
Spring and autumn offer the best balance: fewer crowds at the caves and comfortable surface temperatures. July and August bring heavy crowds, with hourly tours and long lines. Winter remains entirely viable since the caves keep a constant temperature year-round, though Predjama Castle closes earlier and its lower cave level stays shut.
Postojna is a pleasant town, but what makes it really interesting are the activities you can do nearby. I recommend starting with a visit to the caves, which is a super experience, and part of it is done on a little train. Also, do not miss the castle close by that looks like it is coming straight out of the rock.