Slovenia August 2019

A merry gang of twenty-five potholers spent two weeks in Slovenia and visited a dozen caves in the lowland karst.

A short way from Laze is the Planinsko Polje, a large flat-bottomed plain surrounded by wooded limestone hills. Running through this is the river Unica, which resurges from Planinska Jama and disappears into a line of sinks along the edge of the polje. After each time this river resurges and flows across a polje it takes on a different name, hence the moniker ‘The River of Seven Names’. The polje fills and becomes a lake following weeks of heavy rain, flooding the surrounding caves. The hills surrounding the polje have very few surface streams but are scattered with deep holes into large passages.

We eased into the trip with an en masse descent of Logarcek, where a sloping 20m pitch drops into large, dry, horizontal passages with crumbling formations. The guidebook described the next steps as a climb and suggested only a handline. It turned out to be a 30m pitch, so rather underequipped we decided to leave the rest of the cave for later in the week. Two teams returned on separate days to descend the 30m pitch and explore the series of ever more gloomy passages down to sump level. These caves flood slowly from the bottom up so flash flooding is a not a risk. There is a slight risk of getting stuck in thick mud and having to spend several hours cleaning your gear, however.

Next came the cave walk, which is a trail marked through the woods to take you from cave to cave. We spent a few hours trampling through the forest spotting entrances, collecting ticks and keeping an eye out for bears. We later learned that bears only visit in the winter, but some wolves and jackals had been seen in the vicinity. We changed into caving gear to explore Vranja Jama. This is well worth a visit but could probably have been done in normal clothes with a headtorch. We also completed a through trip of Skednena Jama, which required no gear as it’s a simple walk of 200m.

 After messing about in muddy holes for a day it was time to see a proper cave, so we engaged a local guide to take us into Planinska Jama. The guide could only take ten people at a time, so we split into two groups over two days. What a trip! The entrance is a massive resurgence with its own layered cloud system due to the 30°C weather outside. The tour begins with a kilometre of misty walkways constructed during WWI as a secret Italian government project for an underground supply route. The streamway is vast (some 40m by 40m) and continues 500m to an underground confluence where the water from the river Rak from Tkalca cave unites with the river Pivka from Postojnska cave to form the Unica. We reached the edge of a lake and took two inflatable boats to paddle upstream for an hour or so, passing under the decaying Italian walk-way beams with an air of the hobbits paddling elven boats along the Anduin through Mirkwood. The water was practically swarming with proteus, the blind cave salamander native to Slovenia. Proteus (proteus anguinus) are also known as the human fish due to their 100 year lifespan. Eventually we arrived at the upstream sump and explored decorated dry passages known as Paradise. Despite the sore shoulders all round from 4 hours of paddling, we agreed that no trip to Slovenia is complete without a trip into Planinska Jama.

The prospect of a rainy day gave us the perfect opportunity to hide in the show cave Skojanske Jama. Unlike many other show caves in the area, Skojanske Jama’s party trick is not an excess of gobsmacking formations. Instead it has a jaw-dropping underground river canyon of epic proportions. We meandered down the usual dry cave with 5m columns and formations inevitably called the Organ Pipes, wondering why on earth this was a UNESCO site. Suddenly we emerged into the canyon and felt like we were completing a night ascent of an Alpine gorge rather than potholing. Truly one of the most impressive show caves in Europe and well worth a visit. After emerging into heavy rain, we headed for Piran on the Adriatic coast where it was dry and sunny. A swim in the sea, a stroll round an ancient Venetian town, and finally seafood dinner for 22 in a waterside restaurant meant that a fine time was had by all.

We returned to some serious potholing with a descent of Nadjena Jama. A 3m entrance climb is followed by a 25m pitch, and we rigged a 35m rope but the hang is awful, leading to serious rub over flowstone and a set of sharp stals underneath to make the re-belay more painful. The cave is over 5km long an clearly a local gem, so the locals have installed a via ferrata around the side of the pitch, making rigging the pitch completely superfluous. We approached this cave in two teams over two days to avoid congestion. Both teams had a good few hours running around the NW and NE series, admiring some very impressive mud sculptures to rival Mistral’s, checking out the sumps for proteus and getting completely covered in mud.

Next up was the famous Postojnska show cave. This involves hurtling through decorated passages on an 18”-gauge train and certainly made a change from slogging through mud. ‘Well-decorated’ does not do this cave justice and all visitors left replete with their fill of oohs and aahs. The afternoon was rounded off with a visit to Predjama, the castle built into a cave, and a lot of ice-cream.

Another guide was procured for a trip into Krizna Jama, a cave soon to be awarded UNESCO status. The limit was four per trip due to strict conservation rules so eight people went over two days. This cave was particularly significant as Lana’s father was involved with some original exploration and remembered by the guide. The river cave is accessed by boat and is decorated with many beautiful formations, such as ‘the pirate ship’, ‘the jellyfish’ and of course ‘the organ pipes’. Cave conservation was foremost and progress over the calcite barriers between lakes was carefully planned. This cave has also been the site of huge excavations of cave bear skeletons, which can be seen en-route. Trips to the far end of the cave are possible depending on water levels, but we settled for the four hour trip so not to exhaust ourselves.

Back at the muddy end of the spectrum was Mackovica. This is a short and easy trip but has some deceptive route-finding. A mixture of crawling through boulder chokes and some stupendously large passage provided and entertaining hour or two during the heat of the day. Meanwhile the more intrepid cavers descended the Jama Na Meji, a lovely free-hanging daylight shaft of 45m into a large chamber, where SRT skills were challenged and honed. Unfortunately, the way on has collapsed – ‘danger’ means danger in any language! 

Our trip was nearly over, the gear was cleaned and dried ready for the flight home, but the last day held two more caves for us. We walked the delightful Rakov Skocjan gorge along the Rak river using headtorches to explore the caves. Starting upstream with Zelske cave, we visited about half of the 3km cave but skipped the rest, which required a boat. The Rakov Skocjan walk is an easy trail past many karst features, such as large natural limestone bridges. Eventually we reached the downstream end and delved into the large and foreboding Tkalca sink. The cave is 30m wide and had a small streamway but judging by the tree trunks in the roof is a raging expressway in flood.  We walked for about 400m but had to stop due to our lack of diving equipment.

Our speleo-tourism was complete for most although a few went to look down deep shafts in the high karst where the hunt is on for 2000m+ caves. Caving by cable car looks like the way forward until you see the actual caves - more of a serious expedition than a holiday.  The Logatec region of Slovenia is very pretty and with the set up at Speleo Camp it was easy to have a fun fortnight. Everyone headed home with great memories. Many thanks to Dave and Lana Mountain who inspired the trip and organized things on the ground in Slovenia.


The team included David, George, Thomas & Jessica Brock; Dave, Lana, Leon & Eney Mountain; Iain, Jill, Chloe & Emily Crossley; Rob, Lou, Ben, Eve & Cate Chaddock; Tim, Matt, Jude, Molly, Kitty & Charlie Palmer and Dragan, Katerina and Natan. 

We stayed at Speleo Camp, Laze 6b, 1370 Logatec (, run by local caver Frank in a mix of bunkhouse and camping accommodation.  Some flew, some drove, but all agreed that Slovenia is a beautiful, uncrowded, easy European country with welcoming people.  Caving information came from the Caving Guide, Slovenia by Ian Bishop (1997 ISBN 09531312 03). A caving permit is required and, despite Dave’s efforts, ours arrived at Greenclose the week we got back.

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