Fastest 45 min-1 hour by bus
| 🚌 Bus | 45 min-1 hour | Arriva Slovenia from Ljubljana; cave a short walk/taxi from stop |
| 🚆 Train | similar to bus | Station farther from cave entrance than bus stop |
| 🎫 Tour | full day | Bundles cave + Predjama Castle, no direct bus links the two |
| 🚗 Car | ~45 min | ~50 km via motorway; needs vignette; best for both sights in a day |
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The Postojna Cave, one of Europe's largest karst cave systems, is easily reached from Ljubljana in under an hour, and its proximity to the dramatic Predjama Castle, built into a cliff face, means the two are almost always visited together on the same day.
By bus
Regular bus services, including those run by Arriva Slovenia, connect Ljubljana's central bus station to Postojna town in around 45 minutes to 1 hour, with departures running several times a day. From the Postojna bus station, the cave entrance is a further short walk or a quick local taxi ride, since the cave itself sits a little outside the town centre. Buses don't require advance booking outside particularly busy periods, and fares are modest, making this the most budget-friendly independent option.
The one drawback is that Predjama Castle, a highlight for many visitors, doesn't have a direct public bus connection from Postojna town — reaching both sights by public transport in a single day takes some careful planning, or a taxi between the two.
By train
Trains also run from Ljubljana to Postojna, taking a broadly similar time to the bus, though the station is a little further from the cave entrance than the bus stop, adding a short taxi or walk at the end. For most visitors focused specifically on the cave and castle, the bus tends to be the more convenient rail alternative given the stop locations, but train travellers already holding a rail pass may prefer to use it regardless.
Organised day tours
Given the awkward public transport link between Postojna Cave and Predjama Castle, organised day tours from Ljubljana are a genuinely popular and practical option here — most combine entry to both sights with return transport in a single booking, removing the need to coordinate buses, taxis and timed cave tours yourself. This is one of the few day trips where a tour offers a clear logistical advantage over going independently, rather than just convenience.
Driving
Postojna is about 50 km south-west of Ljubljana, roughly a 45-minute drive via the motorway, and driving is the most flexible way to see both the cave and Predjama Castle in one day, since the two sights are only about 15 minutes apart by road but poorly linked by public transport. Slovenia's motorways require a vignette sticker or e-vignette, so check current requirements before you set off. Parking is available at both the cave and the castle. See our guide to driving in Slovenia for the vignette system and general road rules.
What to see once you're there
The Postojna Cave is explored partly by a small underground train and partly on foot, revealing vast chambers, stalactites and stalagmites formed over thousands of years — it's one of the most visited show caves in Europe, and tours run at set times throughout the day, so it's worth checking the current schedule and booking ahead in peak season. The cave is also home to the olm, a strange, pale cave-dwelling salamander sometimes nicknamed the "human fish," on display at the cave's vivarium.
Predjama Castle, a short drive or tour transfer away, is built directly into the mouth of a cave halfway up a cliff face — a genuinely striking sight and one of the most unusual castles in Europe. A network of secret passages connects parts of the castle to the cave system behind it, and the combination of the two sights makes for a full and memorable day out from the capital.
The standard cave tour takes around an hour and a half and covers roughly five kilometres of passages, though only a fraction of the full cave system, most of which remains closed to visitors. The temperature underground stays cool year-round, well below what's comfortable in a summer t-shirt, so it's worth bringing a light jacket even on a hot day outside. Predjama Castle's interior is more modest than its dramatic exterior might suggest, but the setting alone — a castle seemingly grown out of the rock — makes the stop worthwhile, and a circuit of the cliff paths around it offers good vantage points for photographs.
Practical tips for the day
Because cave tours run on a fixed schedule rather than continuously, it's worth timing your bus or train departure from Ljubljana to arrive with enough buffer before the next available tour slot, particularly in shoulder seasons when tours run less frequently than in high summer. Wear comfortable, non-slip shoes, since some of the cave's surfaces can be damp. Combining both sights independently by public transport in a single day is possible with careful planning around taxi transfers, but many travellers find it considerably less stressful to book a tour or drive themselves. If Slovenia is one stop on a longer Schengen-area trip, check the Schengen 90/180 rule so you keep track of your allowed days across the whole trip.
Which should you choose?
If your main goal is the cave alone and you're travelling on a budget, the bus is a perfectly reasonable independent option. If you want to see both the cave and Predjama Castle without the hassle of coordinating separate transport, an organised tour or driving yourself is considerably more practical, given the limited public transport between the two sights. For other easy trips from the Slovenian capital, see our guide to Ljubljana to Lake Bled, or for onward travel, Ljubljana to Venice. Slovenia's compact size makes several such day trips realistic from a single base; see our wider Slovenia & Croatia by train guide for the regional network.
Frequently asked questions
How do I get from Ljubljana to Postojna Cave?
By bus or train to Postojna town, taking around 45 minutes to an hour, followed by a short walk or taxi to the cave entrance. Driving takes about 45 minutes directly to the cave's car park.
Can I visit Predjama Castle and Postojna Cave in one day using public transport?
It's possible but awkward, since there's no direct bus between the two — most visitors either drive, hire a taxi for the short hop between them, or book an organised tour that includes both.
Do I need to book cave tickets in advance?
It's worth booking ahead in peak season, since cave tours run at set times and popular slots can fill up, though tickets are generally available on the day outside the busiest months.
What is the "human fish" at Postojna Cave?
It's the local nickname for the olm, a pale, blind cave-dwelling salamander that lives in the cave's underground waters and is on display at the cave's vivarium.
Sources and further reading:
- Cave and castle visitor information: Postojnska Jama (Postojna Cave) official site.
- Bus timetables and fares: Arriva Slovenia.
- Route context: The Man in Seat 61.