The deepest known cave in the world is Krubera (Voronya) Cave in the Arabika Massif of the Western Caucasus, at 2,224 metres from its highest entrance to its lowest explored point. A 2024 re-survey put it back ahead of neighbouring Veryovkina Cave, which had held the record since 2017 and is now measured at 2,209 metres.
Cave depth is the vertical distance between a cave's highest known entrance and the lowest point anyone has reached, usually the surface of a flooded passage called a sump. Divers who swim down into a sump can add tens of metres to a cave's depth. Accurate surveys can also take metres away, as the 2024 remeasurement showed. The ranking below follows the list maintained by the caving community, and several numbers in it have changed since 2020.
The Record Swap of 2024
For most of the 21st century, the world's deepest cave was in Abkhazia, a breakaway region of Georgia controlled by separatists with Russian backing. Only the name of the cave changed. Krubera held the title from 2001, when a Ukrainian team reached about −1,710 m. In 2004 it became the first cave explored beyond 2,000 metres. Cave diver Gennady Samokhin then extended it through flooded passages at the bottom, to 2,191 m in 2007 and just under 2,200 m in 2012.
In 2017 Veryovkina, a few kilometres away in the same massif, passed it. Russian cavers from the Perovo Speleo Club reached 2,204 m and then 2,212 m in 2018. For the next six years, most books, quizzes and websites gave Veryovkina as the answer.
In August 2024 both caves were re-surveyed with modern instruments, and Veryovkina's bottom sump was tied to a surface lake by precision GNSS positioning. The corrected numbers reversed the order: Veryovkina fell to 2,209 m and Krubera rose to 2,224 m. The 15-metre gap is small compared with the total depth. It shows that these depths are measurements with a margin of error, not exact values.
The reason is how caves are surveyed. Cavers measure a cave one short leg at a time, using a tape or laser range-finder, a compass and an inclinometer, from one survey station to the next. A trip to the bottom of Krubera involves many hundreds of these legs, and a small error in each one adds up over two kilometres of depth. The surface elevation of the entrance also has to be fixed accurately, and older surveys used barometric altimeters or topographic maps that could be off by 10–20 metres. Satellite positioning at the entrance and at the springs where the water reappears now gives the survey fixed reference points at both ends, which is why the 2024 figures are considered more reliable than the ones they replaced.
The Ranking, Deepest First
- Krubera (Voronya) Cave, Abkhazia/Georgia — 2,224 m. About 23 km of mapped passage. Entrance at roughly 2,256 m in the Ortobalagan Valley.
- Veryovkina Cave, Abkhazia/Georgia — 2,209 m. About 17.5 km long, with a notoriously flood-prone bottom section.
- Sarma, Abkhazia/Georgia — 1,830 m. A narrow, cold series of shafts high on the Arabika plateau.
- Tovliani Cave, Abkhazia/Georgia — 1,760 m. About 40 km long, in the neighbouring Khipsta massif. It is the same system long listed under its Russian name, Snezhnaya–Mezhonnogo–Illyuziya. Tovliani is the Georgian word for "snowy", the meaning of Snezhnaya.
- Lamprechtsofen, Austria — 1,727 m. In the Leoganger Steinberge of Salzburg state, with about 61 km of passage.
- Gouffre Mirolda, France — 1,661 m. In the Haute-Savoie Alps, on the Criou massif above Samoëns.
- Gouffre Jean-Bernard, France — 1,612 m. A few kilometres from Mirolda. It was the world's deepest cave in the 1980s.
- Sistema del Cerro del Cuevón, Spain — 1,589 m. In the Picos de Europa, the deepest in the Iberian Peninsula.
- Hirlatzhöhle, Austria — 1,560 m. Under the Dachstein. It is also about 118 km long.
- Sistema Huautla, Mexico — 1,560 m. In the Sierra Mazateca of Oaxaca, the deepest cave in the Western Hemisphere.
Just below the top ten are Chevé Cave in Oaxaca (1,538 m) and Boybuloq in Uzbekistan's Chul-Bair range (about 1,523 m). The rest of the top 15 is made up of Pantyukhin Cave in Abkhazia, Sima de la Cornisa in Spain and Čehi 2 in Slovenia. Several of the lower positions were re-surveyed in 2025 and 2026, so the lower half of any such list changes often.
Why So Many Are on One Mountain
Four of the five deepest caves are in the Arabika Massif and the neighbouring Khipsta massif of the Bzyb Range, just inland from the Black Sea resort of Gagra. Two things make the area unusual. The first is the thickness of the limestone. Arabika is a block of Jurassic and Cretaceous limestone more than 2,000 metres thick, lifted by the same tectonic collision that raised the Caucasus Mountains. The second is how steeply water drops through it. The plateau rises to about 2,700 m, while dye tracing shows its water resurfacing in springs at sea level and even below it, on the floor of the Black Sea. That gives almost 2.5 km of vertical drop for underground water to cut through.
Rain and snowmelt sink through the plateau surface and follow cracks and bedding planes downward, dissolving the limestone into shafts that can be more than 100 m deep. The process is described in our guide to karst landscapes. Arabika is an extreme case of it. For caves to reach these depths, a region needs both thick soluble rock and a big height difference between where water enters and where it comes out. Few places on Earth have both.
What It Takes to Reach the Bottom
Getting to the bottom of Krubera or Veryovkina takes a caving expedition of several weeks. A team of 10 to 20 people rigs thousands of metres of static rope on more than a hundred pitches, carries in food and fuel, and sets up a series of underground camps on the way down, the deepest of them below −2,000 m. The temperature stays a few degrees above freezing, the humidity is close to 100%, and the waterfalls are cold snowmelt. Many explorers spend two to four weeks underground at a time.
Flooding is the most serious danger. In August 2018, a surge of rainwater filled Veryovkina's lower section while a Russian team was at the bottom. The cavers climbed out ahead of the rising water, and all survived. Flood risk is the main reason expeditions happen in late summer, when the snowmelt has passed and heavy rain is less likely.
The caves also contain life. In 2010, researchers in Krubera found a springtail, Plutomurus ortobalaganensis, at 1,980 m below the entrance. It is the deepest land animal ever recorded.
Deepest Cave vs Deepest Mine and Borehole
Natural caves are shallow compared with holes people have dug, and the comparison shows what "deep" means in each case:
- Deepest cave: Krubera, 2,224 m. Explored on foot, on rope and by diving, all through spaces made by water.
- Deepest mine: South Africa's Mponeng gold mine has reached about 4 km below the surface. Rock temperatures there pass 60 °C, so the mine needs industrial cooling to be workable. Our list of the deepest mines in the world covers it in more detail.
- Deepest borehole: The Kola Superdeep Borehole in Arctic Russia reached 12,262 m in 1989. It is only about 23 cm wide, far too narrow for a person.
- Heat is the difference: Caves stay cold because snowmelt keeps flowing through them. Mines and boreholes get hotter the deeper they go, at around 25 °C per kilometre. The Krubera explorers stay only a few degrees above freezing at a depth where a mine shaft in solid rock would be much warmer.
Depth should not be confused with size. The deepest caves are narrow vertical systems, while the largest cave passages are much wider but shallower. Vietnam's Hang Sơn Đoòng has passages more than 200 m high but is not deep, and Mammoth Cave in Kentucky is by far the longest cave but reaches only a modest depth.
Outside the Caucasus: The Alps, Picos and Oaxaca
If the Arabika caves did not exist, the Alps would lead the list. Lamprechtsofen has one of the deepest through-trips in the world: its upper entrances high on the plateau connect to a show-cave entrance near the valley floor at about 660 m, so cavers can travel from top to bottom without climbing back up. The Haute-Savoie caves Mirolda and Jean-Bernard descend through the same limestone that forms the peaks around Samoëns. The Picos de Europa in northern Spain contain several caves more than 1,000 m deep, crowded into a small, steep range.
Mexico's Sierra Mazateca is the deepest caving area in the Americas. Sistema Huautla and Chevé are both around 1,500 m deep and more than 90 km long. Unlike the cold, rope-heavy Alpine caves, they end in long, deep sumps that only cave divers can explore. Boybuloq in Uzbekistan, explored by Soviet and later international teams, is the deepest cave in Asia outside the Caucasus.
No cave has yet been explored below 2,500 metres. Explorers think it could happen in Arabika, where a dry route could reach the Black Sea springs, or in newer areas such as the karst plateaus of Iran and western China. Much of the vertical space inside the Caucasus limestone has still not been explored.
For the horizontal equivalent, where mapped passages run to hundreds of kilometres, see our ranking of the longest caves in the world.