Gruta do Carvão

Carvão Cave

Useful Information

Location: Rua do Paim, 2 Circular, Ponta Delgada, São Miguel.
Open: OCT to MAY Tue-Sun 14:30, 15:30, 16:30.
JUN to SEP daily 10:30, 11:30, 14:30, 15:30, 16:30.
Groups (5+): after appointment.
Classification: ExplainLava Tube
Light: electric.
Dimension: L=1,650m.
Guided tours:  
Bibliography: H. Delgado, J. Nunes, C. Gomes, Z. França (2000): Mineralogy and chemistry of a residual soil developed from pumice argillisation, at Gruta do Carvão, Ponta Delgada - Azore, Proceedings da 1st Latin-American Clay Conference - Clays in Volcanic Environments, Funchal, Vol II; 383-385.
J.C. Nunes, T. Bragaej, P. Constância (2002): Carvão cave (S. Miguel island, Azores, Portugal): an educational experience, Abstracts - Xth International Symposium on Volcanospeleology. Setembro. Reykjavik. Islândia; p. 28.
Address: Reservations: Tel: +351-96-1397080, E-mail: contact
Amigos dos Açores, Associação Ecológica, Sede da Junta de Freguesia do Pico da Pedra, Avenida da Paz, 14, 9600-053 Pico da Pedra, Tel: +351-296-498004, Fax: +351-296-498004. E-mail: contact


11-MAY-2005 classified as a Regional Natural Monument by the Regional Decree nr.4/2005/A.


The Gruta do Carvão lies beneath the streets and buildings of Ponta Delgada. There is another cave with a similar name, called ShowcaveAlgar do Carvão on RegionTerceira. The explanation is easy, Carvão means coal in English, and refers to the black colour of the cave walls. Most of the caves on the islands are lava tubes, and lava very often has this dark black colour. As a result there are various "Coal Pits". Of course, there is no coal found on this islands.

This cave is said to be the longest cave on São Miguel. The length is given with 1,650m, which is a bit strange. In ancient times the cave was reported to be five kilometers long, which obviously was a bad estimation. Today there are three parts of the same lava tube, which are not connected any more. All three parts together have a length of 1,650m.

The entrance is behind a factory, a flight of stairs - lit by a string of light bulbs - leads to a roomy passage. The passage ends where a large stormwater drain broke into the cave ceiling. Gruta do Carvão has extraordinary multi-coloured rock formations with weird shapes. They are the result of lava remains cooling down in the tube.

The cave is a National Monument, and definitely not a show cave. It is not developed, but because of the entrance stair and the huge passage it is easy to visit. During the last years, 1,441 school children have visited the cave. This is part of an environmental education program.