Gruta da Nascente do Almonda / Olho do Moinho da Fonte
Region: Serras de Aire e Candeeiros / Torres Novas
Location: Zibreira / Pedrógão
Type: Major spring cave / multi-river system
Length: >15 km current cave-rescue summary; older underwater paper 9.995 km
Depth: ~ -78 m documented underwater relief; ~1,000 m diveable gallery described
2026 status: PERMISSION / TECHNICAL / ACTIVE EXPLORATION
KCore note: Portugal’s largest known karst network. A ~100 m Christmas Siphon separates old/new sectors; diving remains part of active exploration.
Alviela spring cave
Region: Serras de Aire e Candeeiros / Alcanena
Location: Olhos d’Água do Alviela
Type: Permanent karst resurgence / deep cave
Length: 1,000 m+ published penetration
Depth: -135 m historic; exploration beyond -200 m; -212 m claimed in 2021
2026 status: PNSAC AUTHORISATION / EXTREME
KCore note: Dry-season only because winter flow can make entry impossible; one of Portugal’s deepest active cave-diving projects.
Moinhos Velhos - Pena - Contenda system
Region: Mira de Aire / Minde
Location: Mira de Aire
Type: Large multi-level karst system with permanent siphons
Length: 11 km current published length
Depth: active water table; individual sump depths vary
2026 status: RESEARCH / PERMIT / TOURIST CAVE + SPELEODIVING
KCore note: Final-well dive in 1991 found new passage. SPE cave divers made the physical Moinhos Velhos-Contenda connection on 22 Sep 2023.
Gruta da Contenda - Galeria do Rio
Region: Mira de Aire / Minde
Location: Minde / Mira de Aire
Type: Deep cave river / sump exploration
Length: part of Moinhos Velhos system
Depth: river gallery ~70 m below entrance; >4 h dry approach
2026 status: RESEARCH / EXPEDITION
KCore note: One of Portugal’s few largely virgin underwater-exploration zones.
Gruta da Pena
Region: Mira de Aire
Location: Mira de Aire
Type: Freshwater cave / artificial access well
Length: explored beyond ~800 m penetration
Depth: entry well ~16 m; first 100 m ~6-18 m
2026 status: SPECIAL PERMIT / TECHNICAL
KCore note: Closed artificial well access. Fine sediment can reduce visibility to centimetres; large passage follows beyond.
Olho de Mira / Mindinho-Mira system
Region: Polje de Minde
Location: Mira de Aire / Minde
Type: Karst spring / deep seasonal cave
Length: ~500 m reported development
Depth: at least ~90 m vertical underwater range
2026 status: PNSAC AUTHORISATION / TECHNICAL
KCore note: Season changes logistics: direct wet-season spring dive versus long dry-cave approach when water is low.
Gruta dos Anços
Region: Maciço de Sicó
Location: Soure
Type: Vauclusian spring
Length: ~400 m galleries
Depth: -63 m
2026 status: DRY-SEASON TECHNICAL / VERIFY ACCESS
KCore note: Important Sicó resurgence; rainy-season flow prevents penetration.
Algar das Morenas
Region: Estremoz-Cano anticline
Location: Alandroal
Type: Vertical freshwater cave / phreatic shaft
Length: development incompletely published
Depth: ~ -55 m; water level +/-18 m
2026 status: MUNICIPAL AUTHORISATION / TECHNICAL
KCore note: Two ~10 m shafts to reach water. Not a spring, so year-round diving can be possible.
Gruta da Cova da Velha
Region: Fórnea / Porto de Mós
Location: Alcaria / Porto de Mós
Type: Seasonal spring cave with lakes and siphons
Length: ~1 km
Depth: sump-specific
2026 status: SPELEOLOGICAL / VERIFY ACCESS
KCore note: Straight fault-controlled gallery with lakes and siphons; exploration potential rather than a public dive site.
Gruta Funda
Region: Santa Maria, Azores
Type: Marine lava tunnel + cathedral cave
Length: Long lava tunnel into large chamber
Depth: 15 m tunnel entry; cave entrance ~33 m; max ~40 m
Status: ADVANCED RECREATIONAL CAVE/CAVERN
KCore note: Official Azores site; moderate currents and a cathedral-shaped terminal chamber.
Gruta Azul
Region: Santa Maria, Azores
Type: Marine volcanic cave
Length: Short/moderate
Depth: ~13-17 m
Status: RECREATIONAL CAVERN / LOCAL GUIDE
KCore note: Accessible volcanic cave within Santa Maria’s coastal cave-diving landscape.
Gruta do Paralelo
Region: Santa Maria, Azores
Type: Lava tube
Length: Site-specific
Depth: begins around 15 m
Status: RECREATIONAL/ADVANCED CAVERN
KCore note: Representative island lava-tube overhead dive.
Arcos do Pocinho
Region: Pico, Azores
Type: Lava arches + cave
Length: Short cavern complex
Depth: ~9-23 m
Status: RECREATIONAL / OPEN WATER-CAVERN
KCore note: Two joined lava arches shelter a cave; official Azores tourism classifies it as a cave dive.
Cinco Ribeiras cave complex
Region: Terceira, Azores
Type: Interconnected lava caves / corridors
Length: Multiple linked chambers
Depth: ~12 m average / 16 m max
Status: RECREATIONAL CAVERN
KCore note: Caves linked by corridors and accessed from a sheltered natural swimming pool.
Gruta dos Encharéus / Gruta dos Camarões / Catedral
Region: Various Azorean islands
Type: Marine volcanic cave systems
Length: Site-specific
Depth: shallow to deep recreational/technical
Status: LOCAL DIVE-CENTRE ACCESS
KCore note: Volcanic genesis deserves its own KCore class.
Gruta dos Pampos
Region: Sesimbra / Arrábida
Type: Marine cave with branching interior
Length: Branching cavern; short/moderate penetration
Depth: ~8 m avg / 15 m max
Status: RECREATIONAL CAVERN / CONDITIONS DEPENDENT
KCore note: Large entrance, two branches and diminishing natural light farther inside.
Cavernas do Burrinho
Region: Porto Covo / Alentejo coast
Type: Three marine caves linked by corridors
Length: Three-cave complex
Depth: shallow/moderate
Status: RECREATIONAL / LOCAL GUIDE
KCore note: Useful mainland marine-overhead entry distinct from inland freshwater cave diving.
Gruta da Pombeira
Region: Cascais
Type: Small marine cave
Length: Short
Depth: shallow
Status: RECREATIONAL CAVERN
KCore note: Included for completeness, not as a technical cave-diving destination.
