Visit Postojna Cave and Predjama Castle

Visiting Postojna Cave and Predjama Castle

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We departed the Postojna Cave train inside the hollowed earth and walked in the darkness as our eyes adjusted to the dim lighting. Outside, the Slovenian summer sun was already hot, but 2km deep in the Postojna Cave, the damp air cooled our skin and clung to our clothes. As we stood in the vast space, known as the Great Mountain, we were beginning to see our surroundings more clearly…and we were in awe. This was just the start to our day visiting Postojna Cave and Predjama Castle. 


Slovenia Caves: Postojna Formation

The massive 24km passageway – of which we would walk 1.5km on the Postojna Cave tour – was formed millions of years ago by the underground Pivka River; the water dissolving the limestone and creating open space below the earth’s surface. In the thousands of years that have passed since the Postojna Cave was created, nature has been slowly, but steadily, decorating the interior with an array of rock formations. The stalactites and stalagmites created by water dripping through the earth’s crevices are stacked from the floor and dangling from the ceiling like petrified icicles – creating a beautiful, yet surreal, scene – and make Postojna one of the most famous caves in Slovenia. 


Visiting Postojna Caves, Slovenia

Train ride inside cave at Postojna Cave, Slovenia

Postojna Cave Tour

Although we are not the first or among the few to have seen the inside of Postojna Caves (the Slovenia caves have been open to the public since 1819 and just welcomed their 37 millionth visitor), we felt like explorers discovering the cavernous corridors. We were guided from the Great Mountain across the Russian Bridge into the Beautiful Caves, so aptly named for the fact that it is, indeed, the most beautiful part of the underground Postojna Cave tour.

Spaghetti Hall Stalactites in Postojna Cave, Slovenia

Postojna Cave ‘Rooms’

We walked through three distinct sections (often claimed to be the best caves in Slovenia), which felt like walking through galleries at an art museum. In the Spaghetti Hall, thousands of thin, white stalactites hang from the top of the cave, which to us looked like a shreds of cheese dangling from a giant cheese grater. In the next gallery, the White Hall, enormous, white stalagmites stand like dripping candles; the rocks’ pearly appearance is obtained from concentrated calcium carbonate. In the Red Hall, the stalactites and stalagmites are rust colored, attributed to the iron minerals from the soil above.

Romeo and Juliet Pillar Columns, Postojna Cave, Slovenia

Famous Postojna Rock Formations

Some stalactites and stalagmites in Postojna Cave are so unique that they’ve been nicknamed. The “Leaning Tower of Pisa” resembles the building it is named after; “Romeo and Juliet” are two, long, skinny columns that have joined into one; the “Organ” looks like an organ perched in the church choir and “Brilliant” looks like an enormous diamond on display (although, we think it looked more like a double-scoop of ice cream).

Total Darkness in Postojna Caves

Throughout the cave, two other colors appear – black and green. Black is a naturally occurring pigment from manganese, but the green is mold. The unnatural lights introduced to the interior of the cave facilitate the growth, which is why lights are used sparingly and camera flashes are prohibited. To show us the true darkness of the cave, at one point on the tour, our guide extinguished the lights and we were enveloped in complete blackness.

Cave Creature: Proteus, Olm, Human Fish, Baby Dragon at Postojna Cave

Image courtesy of Postojnska Jama

Postojna Cave Human Fish

Mold, however, isn’t the only thing living in the cave. There are more than 100 species that call Postojna Cave home. Insects and spiders make up the majority of the list, but the most interesting creature to dwell in the cave is the Proteus, also referred to as an Olm, Baby Dragon and, our favorite, Human Fish. The pale pink, salamander-like animal is completely blind, grows to almost 12 inches, lives to be 100 years old and can go without food for 10 years at a time. Since these creatures would be fairly difficult to find naturally within the cave, a large aquarium holding Postojna Cave Human Fish is located inside the cave so that we could get an up-close view. Our visit in the summer of 2016 also coincided with a rare event: the birth of baby Proteus. Although they weren’t yet ready to be formally introduced to the public, we could watch their movements on a video screen.

Postojna Cave Concert Hall

The last ‘room’ on our tour before boarding the train to exit the cave was the Concert Hall. The room holds an echo for five seconds and has been used as a performance hall by various singing groups – and even an in-cave basketball event. Also in the room is the world’s oldest underground post office, which has been post marking parcels since 1899.

Our tour inside Postojna Cave lasted about an hour and a half, but with the “Perfect Experience” ticket, there was more to see. We had access to the on-site, underground zoo and expo center – as well as the nearby Predjama Castle. At the end of our cave tour, it seemed our day was only beginning.


Visiting Vivarium Proteus and Expo Center

The underground zoo, Vivarium Proteus, features the insects and other creatures that inhabit the Postojna Cave. In 1831, the first cave beetle was discovered and it launched a new branch of biology, known as Speleobiology. A small laboratory and display exhibits are located within Vivarium Proteus.

Vintage Posters advertise Postojna Caves, Slovenia

To gain a better understanding of the history of the cave, we visited the expo center. Informative and interesting displays of the creation of the cave, as well as the story of the discovery and promotion of the cave as a tourist sight, were highlighted. Particularly intriguing were the details of how the cave was originally equipped to handle the visitors, including how the cave was lit and the development of the interior railway, which has been in existence since 1872.


Lunch at Postojna Restaurant: Proteus

The Predjama Castle was the final site we would visit, but the castle is actually about 10km from the cave. Before hopping on one of the free shuttles that run guests between Postojna Cave and Predjama Castle, we detoured 1km from the cave to the town of Postojna for a lunch fit for royalty at Proteus Restaurant.

The bright and atmospheric Postojna restaurant serves first class cuisine. Our decadent, two-hour, five-course lunch – of which the highlights were baked octopus in a tomato sauce and glazed lambchops – was complimented with delicious Slovenian wine.


Visiting Predjama Castle

The cliff and cave castle, Predjama, iin Slovenia

When we arrived at Predjama Castle in mid-afternoon, we leisurely wandered the grounds before entering the famous cave castle. An impressive sight, the Slovenia castle is perched in the middle of a 400-foot cliff. Built 800 years ago during the Middle Ages, Predjama Castle was constructed to incorporate a natural cave, which provided secret passageways, a natural water source and hidden rooms. The unique ‘Castle in a Cave’ is unlike any other castle we have ever visited. 

Predjama Castle Tour

When we were ready to tour the Predjama Castle inside, we moved at our own pace through nearly every room soaking up the Predjama Castle history. A free audio guide (offered in multiple languages) is included with admission. In each room of Predjama Castle Slovenia, we were provided a bit of history about how the space was used – from the dungeon to the dining room to the chapel – and even toured the Predjama Castle interior of the natural cave. Visiting the cave castle was yet another highlight of our day! 


Details for visiting Postojna Cave and Predjama Castle

Official Site: Postojnska Jama

Postojna Cave Price: Prices vary depending on which package is purchased. Tickets to Postojna Cave start at 25 euro (at time of writing); however, there are discounts for purchasing a single ticket to multiple attractions. 

Postojna Cave Tickets: Postojnska Jama Ticket Page

Getting from Ljubljana to Postojna Caves: Directions and Transportation Information

With the caves near Ljubljana, it is fairly simple to make a day trip from Ljubljana to Postojna. Even more convenient is that there is a public bus from Ljubljana to Postojna Caves operated by Arriva. Search for the Ljubljana to Postojna Caves bus on the online schedule from Ljubljana (Ljubljana AP) to Postojna Cave (Postojnska Jama). Cost is €6 each way.

Hotel Postojna Jama: The on-site hotel, Hotel Jama, is located just 100 meters from the cave and is highly rated in customer reviews. However, there are other options of hotels in Postojna, which you can search on

What to Wear: The temperature inside the caves is about 46-50˚F year-round. I felt silly carrying a fleece jacket with me in the middle of August, but I was happy to have it after entering the cave! They also rent jackets at the cave entrance for those who come unprepared. Also, make sure you wear good shoes, as the interior of the cave can be slippery. I wore my Columbia shoes, which are great for travel – and Kris wore his Merrells


Ljubljana Caves Tour

While we made our own way from Ljubljana to the caves, there are ample options of Slovenia Cave Tours departing from Ljubljana. If you would rather have a guided tour from the city, check the highly-rated Postojna Cave Tour from Ljubljana on Viator

Trying to decide between visiting Postojna or Skocjan Caves? We loved both! Read about our visit to Skocjan Caves here!


We want to know: Have you visited Postojna Cave and Predjama Castle? What were the highlights for you? What other caves have you visited? Tell us in the comments!

Start planning your trip to Slovenia and to Postojna Cave and Predjama Castle! Search for the lowest airfares, the best accommodations and fun things to do…then start packing!  Want more travel planning tips? Head over to our Travel Planning page for more information and tips on traveling – and for country-specific information, take a look at our Travel Guides page!


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A special thanks to Postojnska Jama for hosting us; as always, the opinions expressed in this post are our own.

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18 thoughts on “Visiting Postojna Cave and Predjama Castle

  1. Danielle

    I think it was these caves that I went to on a family holiday in 1992, when it was still Yugoslavia! details hazy, but does stuck out as v cool! We def rode a train through them!

  2. Jon Dunn

    I did a 6 hour half day tour by minibus this May and we went to the castle first and caves afterwards.
    Our guide new every single thing about the castle and spoke brilliant English – he even had 6 umbrellas in the van which came in dead useful when there was a brief shower of rain!
    Absolutely blew me away, both places !! I’ve been to some wonderful stalactite strewn caves like Nerja in Spain, seen prehistoric cave paintings, and went to an amazing grotto near Alghero, Sardinia, but nothing like this, with a 2 km train ride before you even meet your guide 🙂
    Highly recommend Slovenia Explorer for tours of this type.
    Picked up and dropped off at my hostel. Awesome. Great post and pics, thank you 🙂

  3. Your photos are incredible! I visited Predjama Grad a few years ago and loved it, but we decided upon the Skocjan caves instead, which in retrospect may not have been the best idea, as – although they were amazing inside – we weren’t permitted to take any photos. I actually saw a cave olm in the Jama Baredine caves in Croatia, I cannot believe that they can survive up to 10 years without food!!

    • We hope you make it to the caves and castle – truly fantastic experiences! Taking pictures inside the cave was a little tricky. No flash or tripods allowed…and nothing to stabilize a camera with. However, there are some well-lit sections where we were able to snap a few okay shots. Cheers!

  4. Anonymous

    The Postojna Cave formations are beautiful. Other “walking tour” caves that I have visited are Ohio Caverns and Mammoth Caves. My favorite caves were the “wild caves” that I explored in Kentucky — the only light came from our headlamps — and we relied on maps for guidance!

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