Caving areas

Where Spanish and foreign cavers keep pushing systems tens of kilometres long and more than a kilometre deep. Only the area is shown: getting to these caves is a job for a club.

Picos de EuropaMatienzo and the Four ValleysPorracolina, upper Asón and MieraMortillano, Ramales and the middle AsónOjo GuareñaSierra Salvada and the Losa valleyGorbeia and ItxinaEnkarterri and GaldamesAizkorri-Aratz and AralarLarra and the Piedra de San MartínWestern Aragonese PyreneesTendeñera and PartacuaOrdesa, Monte Perdido and EscuaínCotiella massifSierra de GuaraMontsec and the Lleida pre-PyreneesGarraf massifAlto Tajo and the Serranía de CuencaCalares del Mundo y de la SimaSierra de las NievesSierra de Grazalema and LíbarCazorla, Segura and Las VillasSorbas gypsum karstValencian mountainsMallorcaTenerife lava tubesLanzarote: La Corona lava tubeTeverga, Ubiñas and La Mesa
Caving areas© Instituto Geográfico Nacional (CC BY 4.0)

Longest caves in Spain

#CaveMetres
1Sistema del Alto del TejueloPorracolina, Alto Asón y Miera · Cantabria222,042 m
2Sistema del MortillanoMortillano, Ramales y Asón medio · Cantabria148,608 m
3Sistema de La GándaraPorracolina, Alto Asón y Miera · Cantabria119,000 m
4Ojo GuareñaOjo Guareña · Burgos111,000 m
5Sistema del Hayal de PonataSierra Salvada y Valle de Losa · Araba / Burgos / Bizkaia90,000 m
6Sistema de la Piedra de San Martín – Gouffre des PartagesLarra y la Piedra de San Martín · Navarra (ES) / Pyrénées-Atlantiques (FR)88,111 m
7Sistema de los Cuatro Valles (Four Valleys System)Matienzo y los Cuatro Valles · Cantabria80,249 m
8Cova des Pas de VallgorneraMallorca · Illes Balears78,900 m
9Cueva del Valle (Red del Silencio)Mortillano, Ramales y Asón medio · Cantabria / Bizkaia60,223 m
10Complejo de AtxuriagaEnkarterri y Galdames · Bizkaia57,600 m
11Sistema de Anialarra (Anielarra)Larra y la Piedra de San Martín · Navarra50,177 m
12Itxinapeko sarea (Sistema de Itxina)Gorbeia e Itxina · Bizkaia49,150 m
13Sistema ArañoneraTendeñera y Partacua · Huesca47,500 m
14Cueva VallinaMatienzo y los Cuatro Valles · Cantabria44,542 m
15Ilaminako Sistema (Sistema de las Puertas de Ilamina, BU.56 – A.60)Larra y la Piedra de San Martín · Navarra / Huesca41,767 m
16Sistema de LecherinesPirineo aragonés occidental · Huesca40,910 m
17Sistema de las Fuentes de Escuaín (Sistema Badalona)Ordesa, Monte Perdido y Escuaín · Huesca40,217 m
18Cueva de los ChorrosCalares del Mundo y de la Sima · Albacete38,000 m
19Sistema Cueto – Coventosa – Garma de Bucebrón – Cubera – CorzoPorracolina, Alto Asón y Miera · Cantabria37,258 m
20Sistema de la Peña de MediodíaPirineo aragonés occidental · Huesca35,778 m
21Cueva de UdíasCantabria occidental (Udías) · Cantabria35,196 m
22Sistema de la Vega (South Vega System)Matienzo y los Cuatro Valles · Cantabria35,156 m

Deepest caves in Spain

#CaveMetres
1Sistema del Cuetu'l Cuevón – Torca de las SaxífragasPicos de Europa · Asturias1,589 m
2Sistema de la Cornisa (HG.43) – Torca MagaliPicos de Europa · León1,507 m
3Sistema del Trave (Sistema'l Trabe)Picos de Europa · Asturias1,441 m
4Sistema de la Piedra de San Martín – Gouffre des PartagesLarra y la Piedra de San Martín · Navarra (ES) / Pyrénées-Atlantiques (FR)1,410 m
5Sistema ArañoneraTendeñera y Partacua · Huesca1,349 m
6Sima del Sabbat (B.112 – B.201)Macizo del Cotiella · Huesca1,346 m
7Ilaminako Sistema (BU.56 – A.60)Larra y la Piedra de San Martín · Navarra / Huesca1,340 m
8Sistema Pozu'l Xitu – Cueva CuliembruPicos de Europa · Asturias1,264 m
9Torca de los Rebecos (T.27)Picos de Europa · Asturias1,255 m
10Pozo del MadejunoPicos de Europa · León1,252 m
11Torca de Jou sin Tierre (CS.9)Picos de Europa · Cantabria1,203 m
12Torca Piedras VerdesPicos de Europa · Asturias1,187 m
13Torca del Cueto de los Senderos (Sima 56)Picos de Europa · Cantabria1,169 m
14Torca IdoúbedaPicos de Europa · Asturias1,167 m
15Sistema de las Fuentes de Escuaín (Sistema Badalona)Ordesa, Monte Perdido y Escuaín · Huesca1,151 m
16Sistema Hulagua (Asopladeru la Texa – Tormenta)Picos de Europa · Asturias1,102 m
17Torca la Monda (L.652)Picos de Europa · León1,063 m
18Sistema Cembavieya – Ḥou de la Canal Parda – Canalón de los DesvíosPicos de Europa · Asturias1,061 m
19Sistema Sima GESM – Sima de la LuzSierra de las Nieves · Málaga1,059 m
20Sistema Castil (PC.15) – Carbonal (CT.14)Picos de Europa · Asturias1,028 m
21Torca UrrielluPicos de Europa · Asturias1,022 m
22Sistema de LecherinesPirineo aragonés occidental · Huesca1,009 m

Picos de Europa

Asturias · Cantabria · Castile and León · Asturias, Cantabria, León · limestone (high-mountain karst)

A high limestone massif shared by Asturias, Cantabria and León, made of three blocks: the western Cornión, the central Urrieles and the eastern Ándara. It is the heart of deep caving in Spain, holding most of the country's caves deeper than a thousand metres; by late 2025 the Asturian federation counted fifteen in this massif alone. Spanish and foreign club expeditions, from Britain, Poland, France and elsewhere, return every summer.

Protection

Main systems

Who explores here

Oxford University Cave Club (Western Massif / Ario, since 1961) · Ario Caves Project (Western Massif, 2013–2022) · Tresviso Caves Project (Eastern Massif / Ándara) · Speleoclub Wrocław and other Polish clubs (Cembavieya – Canal Parda) · Polski Związek Alpinizmu · SCOF (French club; Pozu TMT, Torrezuela per CGCE) · Grupo de Espeleología Matallana (León sector) · Federación d'Espeleoloxía del Principáu d'Asturies (FESPA)

Surveys and reports

Matienzo and the Four Valleys

Cantabria · Cantabria · limestone

A closed basin of about 26 km² ringed by limestone hills in the municipality of Ruesga, some 30 km south-east of Santander. Since the late 1960s British-led expeditions, working with Spanish groups, have recorded over 5,500 sites and more than 440 km of passage. Its main networks are the Four Valleys System, now over 80 km long, and Cueva Vallina.

Main systems

Who explores here

Matienzo Caves Project (British-led, with Spanish groups)

Surveys and reports

  • Matienzo Caves Project ↗Matienzo Caves Project (Juan Corrin, curator) — Cave descriptions and surveys for 5,577 sites, full logbooks and yearly reports, site-description PDFs, centre-line/3D data, maps, science pages, and Cantabria Subterránea 2010 volumes.

Porracolina, upper Asón and Miera

Cantabria · Castile and León · Cantabria, Burgos · limestone (Cretaceous)

A limestone massif at the headwaters of the Asón and Miera rivers, spanning Arredondo, Soba, Ruesga and San Roque de Riomiera and reaching into Espinosa de los Monteros. It holds two of Spain's three longest caves, the Alto del Tejuelo system (over 220 km) and La Gándara, plus the classic Cueto–Coventosa system. Spanish, French and Belgian teams work different sectors and publish inventories and yearly reports.

Protection

Main systems

Who explores here

C.M.E. Proteus (Cantabria) · Club de Espeleología SECJA (Alcobendas) · Speleologieclub K.U. Leuven (SpeKUL) · Agrupació Científico Excursionista de Mataró (ACEM) · Karstexplo (French team; site by P. Degouve & G. Simonnot) · AEM Trasmiera (cited by CGCE for Coventosa) · Club Cántabro de Exploraciones Subterráneas (CCES) blog

Surveys and reports

Mortillano, Ramales and the middle Asón

Cantabria · Cantabria · limestone

Limestone hills between Soba, Ramales de la Victoria and Rasines in the middle Asón valley. The Mortillano system, explored mainly by the Agrupación Espeleológica Ramaliega, is about 148 km long and ranks second in Spain. Nearby lie the Cullalvera show cave, the Carcabón and Cueva del Valle with its Red del Silencio.

Main systems

Who explores here

Agrupación Espeleológica Ramaliega (AER) · Blog Valle del Asón (AER activity blog)

Surveys and reports

Ojo Guareña

Castile and León · Burgos · limestone

A karst complex in northern Burgos, in the Merindad de Sotoscueva, made of many caves linked on several levels and drained by the Guareña river and its tributaries. Over 110 km have been surveyed, and the site matters for archaeology and cave biology as much as for caving. The Grupo Espeleológico Edelweiss has studied and published on it for decades.

Protection

Main systems

Who explores here

Grupo Espeleológico Edelweiss (Burgos)

Surveys and reports

Sierra Salvada and the Losa valley

Basque Country · Castile and León · Araba/Álava, Bizkaia, Burgos · limestone

A long limestone escarpment that divides the Burgos upland of the Losa valley from the lowlands of Ayala (Álava) and Orduña (Bizkaia). Beneath its plateau runs the Hayal de Ponata system, about 90 km long on the latest figures, along with other networks such as Pozalagua.

Main systems

Who explores here

Grupo Espeleológico Alavés (GEA) · Grupo Espeleológico Takomano · Grupo Espeleológico Edelweiss

Surveys and reports

Gorbeia and Itxina

Basque Country · Bizkaia, Araba/Álava · limestone (Urgonian)

Itxina is a large limestone outcrop inside Gorbeia Natural Park, between Bizkaia and Álava, with karren fields, sinkholes and beech woods. Beneath it lies Itxinapeko sarea, one of the largest cave networks in the Basque Country, and on the Álava side of Gorbeia is the Mairuelegorreta system.

Protection

Main systems

Surveys and reports

Enkarterri and Galdames

Basque Country · Bizkaia · limestone (karst intersected by old iron mines)

An area of western Bizkaia where natural caves are crossed by old iron-mine workings. At Galdames the Atxuriaga complex links several caves for over 57 km, and the area also includes the Urallaga complex.

Main systems

Who explores here

Grupo Espeleológico Burnia (Galdames)

Surveys and reports

Aizkorri-Aratz and Aralar

Basque Country · Navarre · Gipuzkoa, Araba/Álava, Navarra · limestone

Limestone ranges on the watershed between Gipuzkoa, Álava and Navarra. Around Oñati and Arantzazu lie the Gesaltza–Arrikrutz complex, partly open to visitors, and other caves several kilometres long; Aralar, shared with Navarra, is another long-standing shaft area.

Protection

Main systems

Who explores here

AMET (blog espeleoamet, cited by CGCE for the Oñati caves)

Surveys and reports

Larra and the Piedra de San Martín

Aragon · Navarre · Navarra, Huesca · limestone (bare high-mountain karst)

A largely bare high-mountain karst straddling the border between Navarra, Huesca and the French Basque Country. It is one of the most historic karsts in European caving: the Pierre Saint-Martin system is over 1,400 m deep and 88 km long, and Anialarra and Ilamina open on the Spanish side. Exploration is coordinated through ARSIP with French and Spanish clubs.

Protection

Main systems

Who explores here

ARSIP – Association pour la Recherche Spéléologique Internationale à la Pierre Saint-Martin · GAES (blog; cited by CGCE for Anialarra) · Satorrak Espeleología (Navarra)

Surveys and reports

Western Aragonese Pyrenees

Aragon · Huesca · limestone

Limestone ranges between the Hecho, Aragüés, Aísa, Borau and Canfranc valleys. The highlights are the Lecherines system in the Aspe massif and the Peña de Mediodía system in the Bernera range, both over 35 km long; Lecherines is more than a thousand metres deep and Peña de Mediodía about nine hundred.

Protection

Main systems

Who explores here

Centro de Espeleología de Aragón (CEA) – Lecherines

Surveys and reports

Tendeñera and Partacua

Aragon · Huesca · limestone

Limestone ranges between the Tena and Broto valleys, west of Ordesa. They hold the Arañonera system, Aragón's deepest cave (–1,349 m and about 47 km), explored over more than fifty campaigns by the Espeleo Club Muntanyenc Barcelonès, and the PE-6 shaft in the Partacua range.

Main systems

Who explores here

Espeleo Club Muntanyenc Barcelonès (ECMB) – Arañonera campaigns

Surveys and reports

Ordesa, Monte Perdido and Escuaín

Aragon · Huesca · limestone

The Monte Perdido limestone massif and its canyons (Ordesa, Añisclo, Escuaín), inside the national park. At Escuaín the Grup d'Espeleologia de Badalona explores the Fuentes de Escuaín system, over 40 km long and 1,151 m deep; the high ground also holds ice caves and alpine shafts.

Protection

Main systems

Who explores here

Grup d'Espeleologia de Badalona (GEB)

Surveys and reports

Cotiella massif

Aragon · Huesca · limestone

An isolated limestone massif in Sobrarbe, within the Sobrarbe-Pirineos Geopark. The Asociación Científico Espeleológica Cotiella, based in Plan, coordinates exploration and study of deep shafts such as Sima del Sabbat (–1,346 m) and publishes the journal Cotiella.

Protection

Main systems

Who explores here

Asociación Científico Espeleológica Cotiella (ACEC)

Surveys and reports

Sierra de Guara

Aragon · Huesca · limestone and conglomerate

Pre-Pyrenean ranges of limestone and conglomerate, best known for canyoning. The longest known cave is the Solencio de Bastarás, just over 8 km.

Protection

Main systems

Surveys and reports

Montsec and the Lleida pre-Pyrenees

Catalonia · Lleida · limestone; conglomerate (Cova Cuberes)

Pre-Pyrenean limestone ridges of Pallars Jussà and La Noguera; the Montsec alone has over 150 recorded shafts and caves. The standout is Cova Cuberes, formed in conglomerate and reported as Catalonia's longest cave at about 13.5 km.

Main systems

Surveys and reports

Garraf massif

Catalonia · Barcelona · limestone

A coastal limestone massif south-west of Barcelona, protected as a natural park, with about five hundred known shafts. The deepest is the Avenc de l'Esquerrà, around 235 m according to park material.

Protection

Main systems

Surveys and reports

Alto Tajo and the Serranía de Cuenca

Castilla–La Mancha · Guadalajara, Cuenca · limestone and dolomite

High limestone plateaus and gorges of the Iberian Range between Guadalajara and Cuenca, with extensive karst of canyons, collapse dolines and sinks. Notable caves include Cueva del Tornero in the Alto Tajo and the Embasado–Tío Vitejo system in Cuenca.

Protection

Main systems

Who explores here

GAEM (cited by CGCE for Embasado–Tío Vitejo) · Agrupación Espeleológica GET

Surveys and reports

Calares del Mundo y de la Sima

Castilla–La Mancha · Albacete · limestone and dolomite

Limestone uplands at the head of the river Mundo, in Riópar. Cueva de los Chorros, which feeds the river's spring, is over 38 km long according to the national catalogue and is among the largest caves in southern Spain; caving trips are limited by quota.

Protection

Main systems

Who explores here

Grupo de Espeleología del Centro Excursionista d'Alcoi (first survey, 1965)

Surveys and reports

Sierra de las Nieves

Andalusia · Málaga · limestone and dolomite

A limestone and dolomite range in the Serranía de Ronda, a national park since 2021, with deep shafts on its high ground. In September 2025 the caving section of the Sociedad Excursionista de Málaga confirmed the link between the Nevero and Aire shafts, creating Andalusia's largest system (26.4 km, –955 m); nearby is the GESM–Luz system at –1,059 m.

Protection

Main systems

Who explores here

Grupo de Exploraciones Subterráneas de la Sociedad Excursionista de Málaga (GES de la SEM) · Interclub Sierra de las Nieves

Surveys and reports

Sierra de Grazalema and Líbar

Andalusia · Cádiz, Málaga · limestone

Limestone ranges between Cádiz and Málaga, among the wettest in Iberia, with very active karst. A river sinks at the Hundidero cave and reappears at the Gato cave, forming one of Andalusia's best-known through-trips, which is subject to access rules.

Protection

Main systems

Surveys and reports

Cazorla, Segura and Las Villas

Andalusia · Jaén · limestone and dolomite

A large group of limestone and dolomite ranges in eastern Jaén where the Guadalquivir rises. The Grupo de Espeleología de Villacarrillo has studied its karst and cave fauna for decades; one of the largest caves is the Arroyo de la Rambla complex (PB-4).

Protection

Main systems

Who explores here

Grupo de Espeleología de Villacarrillo (GEV), bulletin Gota a Gota

Surveys and reports

Sorbas gypsum karst

Andalusia · Almería · gypsum

A gypsum landscape in central-eastern Almería with sinkholes, tunnels and caves dissolved under a semi-arid climate. Its main network, Cueva del Agua, is over 9 km long and ranks among the largest known gypsum caves.

Protection

Main systems

Who explores here

Espeleo Club Almería (Topo Sorbas camps) · AAES (blog cited by CGCE)

Surveys and reports

Valencian mountains

Valencian Community · Castellón, Valencia, Alicante · limestone (some gypsum and sandstone)

Not one massif but many limestone ranges across the three provinces, with thousands of recorded caves; the Castellón catalogue kept by Espeleo Club Castelló alone lists over 7,000. Caves are smaller than in the north, with systems of around 7 km such as Cova de l'Autopista and Sima Posos.

Main systems

Who explores here

Espeleo Club Castelló (ECC) · Club Castell de Serra (blog)

Surveys and reports

Mallorca

Balearic Islands · Illes Balears · limestone

The island pairs mountain karst in the Serra de Tramuntana, with shafts over 300 m deep, with coastal karst in the south and east where large, partly flooded caves are also explored by divers. Cova des Pas de Vallgornera, nearly 79 km long, is the largest in the Balearics; many caves are protected sites that require a permit.

Protection

Main systems

Who explores here

Societat Espeleològica Balear (SEB) · Federació Balear d'Espeleologia (journal Endins)

Surveys and reports

Tenerife lava tubes

Canary Islands · Santa Cruz de Tenerife · volcanic (basaltic lava tubes)

A volcanic island with lava tubes formed under basaltic flows. The Cueva del Viento–Sobrado system at Icod de los Vinos totals about 18.5 km on several levels and is one of the world's longest lava tubes; a short section can be visited with a guide from its visitor centre.

Protection

Main systems

Surveys and reports

Lanzarote: La Corona lava tube

Canary Islands · Las Palmas · volcanic (basaltic lava tubes)

A volcanic island whose best-known tube is La Corona in the north, which continues under the sea as the Túnel de la Atlántida. It includes the Cueva de los Verdes and Jameos del Agua, both open to visitors, plus other tubes explored in recent years.

Protection
  • Lanzarote y Archipiélago Chinijo Geopark (mentioned by lanzarotecaves.com; official page not checked) Source: Lanzarote Caves

Main systems

Surveys and reports

Teverga, Ubiñas and La Mesa

Asturias · Asturias · limestone

Limestone mountains of the Cantabrian Range around Las Ubiñas–La Mesa Natural Park. Cueva Huerta in Teverga is a natural monument and one of Asturias' largest caves, although published lengths range from about 14 to nearly 24 km.

Protection

Main systems

Surveys and reports

Data checked in October 2026. Spot a mistake or a missing cave? Tell us.