Cave diving in Slovenia
A handful of karst springs — the deep Divje jezero near Idrija (-160 m), the Retovje springs of the Ljubljanica near Vrhnika and the Bilpa on the Kolpa — plus research caves such as Planinska jama; under the Slovenian diving act foreigners may only dive them after notifying the police and together with a qualified Slovenian diver.
8 caves · down to 160 m · 1 suitable for an intro team
All 8 caves
| Site | Max depth | Type | Certification |
|---|---|---|---|
| Bilpa | – | Not known yet | Full cave |
| Divje jezero | 160 m | Not known yet | Full cave |
| Izvir Krupe | 7 m | Small cylinders / no-mount | Full cave |
| Luknja pri Plavah | 24 m | Not known yet | Cavern |
| Malo okence (Retovje) | 45 m | Not known yet | Full cave |
| Nova Križna jama (Dihalnik v Grdem dolu) | 153 m | Not known yet | Full cave |
| Planinska jama | – | Not known yet | Full cave |
| Veliko okence (Retovje) | 25 m | Not known yet | Full cave |
Certification requirements, configurations and trimix depths are estimates for planning. Always check them locally and dive within your training.
Practical info: rules, fills and emergency numbers
Emergencies
- 112 — the regional dispatch centre also reaches the underwater rescue service; in cave accidents the cave rescue service JRS turns out. Chambers (SPZ list 2021): Ljubljana, Medical Faculty, Zaloška 4 (8-person chamber), +386 1 543 7537; mobile one-person transport chamber in Ankaran, duty number +386 5 652 8118; Trieste (IT), Strada di Fiume 447, +39 040 399 4720; Rijeka (HR), KBC Rijeka, Tome Strižića 3, +385 51 407 435; Pula (HR), OXY, Santoriova 24a, +385 52 215 663. Always call ahead. DAN Europe +39 06 4211 5685.
Access and rules
- Law for foreigners: diving in caves, mines, springs, underground rivers and under ice is 'technical diving' under the Slovenian Drowning Protection Act (ZVU, 2000). Foreigners may only do it after notifying the local police station of place and time (you get a confirmation), with accident and life insurance, proof of training, and together with a qualified Slovenian diver. The police still pointed this out at the Bilpa in 2009; check with a Slovenian dive centre or the Slovenska potapljaška zveza (SPZ) whether it still applies.
- Caves are state property and protected (ZVPJ): caves with free access, with controlled access (registered and supervised entry only) and closed caves (research only, with a ministry permit). Motorised vehicles and craft are banned in caves; electric scooters are only allowed for sump research. The Jamarska zveza Slovenije (JZS) tests cavers, keeps the cave register and runs the cave rescue service (JRS).
- Nature and drinking water: the minister can regulate or ban diving in nature- and water-protection areas (ZVU). For dive sites in Triglav National Park the SPZ atlas asks for the park's (TNP) consent; Zelenci needs a special permit. Divje jezero and the Krupa are natural monuments.
Gas and fills
- Gas: Norik-sub in Ljubljana fills air, nitrox, O₂, trimix and heliox to 300 bar (Mon–Fri 9:00–18:00). Društvo Kisik – Oxygen (watersports.si, Bled) fills air to 232 bar and nitrox up to 40%; trimix and O₂ on request. Both teach CCR courses; sofnolime: ask.
Water and season
- Water: karst springs are cold year-round (Kamniška Bistrica max 6 °C, the Ribnica springs ~7 °C, Krupa ~10 °C in summer): drysuit. After heavy rain springs such as the Bilpa and Divje jezero flow hard. Slovenian cave divers dive all year.
Safety
- Compressed air is allowed to -40 m in Slovenia; deeper you dive on trimix (ZVU).
Getting around
- Bases: Ljubljana (central, fill station), Vrhnika (Retovje), Idrija (Divje jezero), Postojna (Planinska jama), Kočevje (Bilpa) or Semič (Krupa).
Rest day
- Rest day: Idrija (UNESCO Global Geopark), the circular walk past the Retovje springs, or a visit to Planinska jama.
Good to know
- Coast: the Slovenian coast at Piran has reefs and wrecks but no known sea caves.
Plan a cave diving trip to Slovenia
Enter your team, with certifications, gas and configurations, and see right away which caves fit. With driving times from your stay, fill stations and an AI instructor who thinks along.
Compiled from web research (Drowning Protection Act ZVU, Uradni list RS 44/2000; Cave Protection Act ZVPJ via JZS; 24ur Jan 2009 and the JZS rescue archive; Svet24 Dec 2025; RTV SLO Jul 2026; Radio Ognjišče; the Slovenian diving federation's PAS atlas and emergency list (2021); Wikipedia; kraji.eu; Moja jezera; Kam na izlet; Dolenjski kras (JKNM); X-Ray Mag and InDEPTH (2020); wannadive.net; potapljanje.si; Norik-sub and watersports.si; visit-idrija.si; Sept 2026). Pins from Wikipedia, the SPZ atlas and Kam na izlet; three sites have no pin. ~ = estimate. Rules change — check locally.