Cave Dive World · country catalogue
Vouliagmeni · Devil’s Well · Kefalonia · Gourgouthakas · Lavrio · marine caverns · archaeology.
approved research integrated · v0.1
Professional catalogue v0.1 — September 2026
country contents
Jump to a section. Cave Finder links land directly on individual cave/system cards where available.
Greece · research catalogue
Greece combines the warm urban cave beneath Vouliagmeni, Kefalonia’s island aquifer siphons, Crete’s deep caver-first sump expeditions, Lavrio’s flooded mine galleries and a broad recreational marine-cavern culture.
Greece · research catalogue
Region: Vouliagmeni / Attica
Type: DEEP THERMAL-BRACKISH UNDERWATER CAVE
Scale: 3,123 m explored in 2003 source; furthest 788 m straight-line; commonly -60 to -100 m; low ceiling point ~-105 m
Status: RESEARCH / TECHNICAL / ACCESS CONTROL
KCore note: Huge urban cave with fresh/salt mixing and ~27°C water below ~40 m.
Region: Vouliagmeni / Attica coast
Type: VERTICAL SHAFT + NEGATIVE-FLOW CAVE
Scale: Shaft 11-28.5/29 m; ~145-200 m cave explored
Status: ENTRANCE AREA ACTIVE / CAVE GATED-HAZARDOUS
KCore note: 1978 triple fatality, later recovery evidence and 2026 CCR fatality; strong inward flow.
Region: Kefalonia
Type: BRACKISH COASTAL AQUIFER CAVE
Scale: Southern siphon ~240 m; chambers in first 180 m
Status: SHOW CAVE / RESEARCH / HISTORIC DIVING
KCore note: Major Kefalonia aquifer-window and 2001 HUE expedition site.
Region: Kefalonia
Type: COLLAPSE DOLINE + UNDERWATER CHAMBER / SIPHONS
Scale: Visible cave ~75 m; second chamber ~85 × 58 m; lake depth ~4-5 m
Status: RESEARCH / HISTORIC CAVE DIVING
KCore note: Two brackish lakes and unresolved siphons.
Region: Kefalonia
Type: LONGER UNDERWATER CAVE / EXPEDITION
Scale: Deep dry approach; long penetration route; 2001 HUE project
Status: EXPEDITION / ACCESS VERIFY
KCore note: One of the harder Kefalonia cave-diving objectives.
Region: Akrotiri, Chania / Crete
Type: MARINE CAVERN + AIR CHAMBER / PALEONTOLOGY
Scale: ~40 m underwater tunnel to large chamber; overall cave >100 m
Status: ACTIVE / GUIDED / PALEONTOLOGY
KCore note: Pleistocene elephant fossils and submerged speleothems.
Region: Crete
Type: MARINE CAVE / AIR CHAMBER
Scale: Entrance ~17 m; cave ~30 m; vertical route to air room
Status: ACTIVE / ADVANCED / GUIDED
KCore note: Short genuine marine overhead with freshwater seepage.
Region: Lefka Ori / Crete
Type: DEEP INTERNAL SUMP / CAVER-FIRST EXPEDITION
Scale: Sump at ~-1,100 m cave depth; 2025 dive added ~80 m to -1,129 m
Status: EXPEDITION / EXTREME / ACTIVE FRONTIER
KCore note: One of the purest caver-first sump operations in the catalogue.
Region: Lefka Ori / Crete
Type: DEEP INTERNAL SUMP / ACTIVE RIVER CAVE
Scale: ~1,100 m cave-depth class; terminal sump
Status: EXPEDITION / FRONTIER
KCore note: Major future target; rain/flooding dominates access.
Region: Lavreotiki / Attica
Type: FLOODED HISTORIC MINE / ARTIFICIAL OVERHEAD
Scale: 2010 lower-level dive >100 m penetration; later 2019-20 projects
Status: EXPLORATION / HISTORIC INDUSTRIAL
KCore note: Verified genuine Greek flooded-mine exploration.
Region: Zakynthos
Type: MARINE CAVERN / SEA-CAVE NETWORK
Scale: Mostly shallow-to-mid-depth recreational routes
Status: ACTIVE / RECREATIONAL / CONSERVATION
KCore note: High-density sea-cave tourism with turtle-park context.
Greece · research catalogue
The visible warm brackish lake is only the entrance to a much larger flooded system beneath Mount Hymettus. HUE’s 2003 summary gives 3,123 m explored and a furthest surveyed point 788 m from the entrance in straight-line distance. Historical descriptions place much of the cave around 60-100 m, with a low ceiling point around 105 m.
Below roughly 40 m the water stabilizes near 27°C. The cave is both a technical exploration site and an urban karst laboratory.
Greece · research catalogue
The coastal shaft begins around 11 m and drops to roughly 28.5-29 m before a cave extends inland. Persistent inward flow can make entry easier than exit, particularly around restrictions.
Three American divers disappeared in 1978; later Greek teams recovered evidence/remains over a multi-year process. In March 2026 an experienced Greek CCR diver also died in the system and was recovered by specialists.
Greece · research catalogue
Kefalonia’s submerged caves belong to an island-scale coastal aquifer where seawater and groundwater move through karst from the Argostoli side toward Sami/Karavomylos.
Greece · research catalogue
Elephant Cave combines a roughly 40 m underwater tunnel with a large partly air-filled chamber containing Pleistocene elephant remains and speleothems. It is commonly offered as a guided marine-cavern dive but its fossil material is protected.
El Greco begins around 17 m and extends roughly 30 m toward an air chamber. It is short and guided, but still genuine overhead rather than open-water rock scenery.
Greece · research catalogue
In August 2025 the Gourgouthakas-Liontari expedition reached the terminal sump at about -1,100 m cave depth. The dive added roughly 80 m of underwater passage and extended the surveyed cave to -1,129 m.
The operation required major vertical-caving logistics, underground camps, rope descents, hauling and communications. The scuba portion was small relative to the whole expedition but moved the surveyed limit — a defining Cave Dive World caver-first example.
Greece · research catalogue
Liontari lies near Gourgouthakas and carries an active underground river toward a terminal sump in the ~1,100 m cave-depth class. The 2025 campaign reached only about 700 m because rain made deeper work unsafe. Weather and flood hydrology dominate long before a diver reaches the water.
Greece · research catalogue
On 23 January 2010 Argyris Argyriadis conducted a documented lower-level mine dive starting on the fifth level about 80 m below surface and roughly 400 m from the entrance. He entered the submerged sixth level and penetrated more than 100 m at only about 4.5 m underwater depth.
Further 2019-20 projects in Plaka and Agios Konstantinos documented flooded galleries. Lavrio is therefore a verified artificial-overhead environment, not an open quarry.
Greece · research catalogue
Zakynthos, Crete and other islands add a broad layer of shallow sea caves, arches and tunnels, mostly recreational light-zone environments. Greece also has an exceptional underwater cultural-heritage layer managed by the Ephorate of Underwater Antiquities.
KCore distinguishes archaeological visitation from wreck penetration: an amphora field or controlled wreck park is heritage diving, not automatically enclosed overhead.
Greece · research catalogue
Greece · research catalogue
Greece · research catalogue
Greece · research catalogue
Frontier: Extensive mapped cave still does not equal a complete hydrological model.
Frontier: Possible wider karst relationship remains unproven as a physical human connection.
Frontier: Melissani and Zervati point into a much broader island groundwater network.
Frontier: The 2025 sump extension may be only the first underwater step beyond -1,100 m.
Frontier: Major deep target still constrained by weather and flood risk.
Frontier: Vast mining district relative to short underwater sections documented so far.
Frontier: Many coastlines likely contain more named and unnamed cavern passages, most recreational rather than full cave.
Greece · research catalogue
Greece · research catalogue
