5 caves · down to 215 m
Cave diving in the Maciço Calcário Estremenho
- Caves5
- Max depth215 m
- Water temperature10–19 °C
Why come here
In the Maciço Calcário Estremenho, inside the Serras de Aire e Candeeiros natural park, lie karst springs for full cave divers. The Alviela, right by Amiais de Baixo, is Portugal's deepest cave at -215 m and can only be dived in the dry season with the park's authorisation, because current and flow are too strong in the rainy season. The Gruta da Pena is the opposite: normally dry, it only floods in wet winters, when the water is often crystal-clear and around 15 °C, and it needs a special permit from the local authorities. No public fill station for trimix or oxygen has been confirmed in the region, so arrange your gas in advance.
Don't miss
- Nascente do Alviela (Olhos de Água): a permanent karst spring where teams have gone ever deeper since 1961, from -35 m on the first dive to -215 m in 2020.
- Gruta da Pena (Mira de Aire): a large chamber with sparkling walls and a column to tie your line to, often crystal-clear in winter.
On a rest day
- Centro Ciência Viva do Alviela: The science centre by the Alviela spring, about the region's limestone, the spring and the bats in its caves.
- Mira de Aire Caves: Portugal's largest show caves, in the same limestone massif.
- Aire Range Dinosaur Tracks: A former quarry with Middle Jurassic sauropod tracks, including a 147 m trackway that was the longest known sauropod trackway in the world when it was found.
- Batalha Monastery: The Gothic monastery of Batalha, a UNESCO World Heritage Site.
All 5 caves
2 closed not shown ·
| Site | Max depth | Type | Certification |
|---|---|---|---|
| Gruta da Pena (Mira de Aire)Permission neededNot known yet · Full cave | 120 m | Not known yet | Full cave |
| Nascente do Alviela (Olhos de Água)Permission neededNot known yet · Full cave | 215 m | Not known yet | Full cave |
| Olho de Mira (Mira de Aire)Permission neededNot known yet · Full cave | 90 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.
Map
Where to stay
Find a place near Amiais de Baixo, Alcanena, Torres Novas
Villages that work well as a base for the caves in this region. Find a place for your team:
- Amiais de BaixoBooking.com ↗
- AlcanenaBooking.com ↗
- Torres NovasBooking.com ↗
The links to Booking.com are affiliate links: if you book through one, DiveTripPlanner earns a small commission. You pay the same.
Practical info: rules, fills and emergency numbers
Emergencies
- 112; DAN Europe +39 06 4211 5685.
Access and rules
- Access: the caves lie in and around the Serras de Aire e Candeeiros natural park (PNSAC). Alviela needs PNSAC authorisation, the Gruta da Pena a special permit from the local authorities; the Almonda has two entrances (the spring by the Renova dam and an artificial pit in Vale da Serra) and both are closed: exploration teams with permission only.
Gas and fills
- Gas: no public fill station for trimix or oxygen confirmed in the region; according to GUE, teams had to arrange their own fills. Arrange your gas in advance.
Water and season
- Season: Alviela only in the dry season (in the rainy season the current and flow are too strong); the Gruta da Pena on the contrary only in wet winters, when the normally dry cave floods.
Getting around
- Base: Amiais de Baixo lies right by the Alviela spring; Mira de Aire (Gruta da Pena) and Torres Novas (Almonda) are ~15–25 km away (estimate).
Rest day
- Rest day: the Centro Ciência Viva do Alviela at the spring, and the Mira de Aire show cave.
News
No recent news found about the caves in this region.
Searched automatically, last on 5 Nov 2026.
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