Gruta de Arbedales

Gruta de Arbedales is a natural cave in the parish of Pillarno, in the municipality of Castrillón, on the coast of Asturias. It formed through karst erosion of Devonian-era limestone, and its existence came to light by chance in 1963, when Manuel del Busto uncovered the entrance during work at a nearby limestone quarry. Since then the cave has been opened to visitors as a privately run site.

What will you see inside?

The section open to visitors covers roughly 600 m², with a main chamber of about 150 m² and a ceiling reaching around 20 meters high. Inside, you'll find dense clusters of stalactites and stalagmites, built up over time from calcium carbonate deposited by water seeping through the rock. Several of the most distinctive formations have their own names, including "La Costa Verde," "La Cascada de Algas," and "La Pagoda del Diablo" — their shapes suggest a green cascade or a pagoda-like structure, making the visit visually striking even for people without a particular interest in geology. The cave maintains a constant internal temperature of around 14°C year-round, which is worth factoring into what you wear.

How do you get to Gruta de Arbedales?

The cave sits in the municipality of Castrillón, in northern Asturias, an area known for coastal walking and cycling routes — the mountain-bike trail "Engañando al Pulide" passes near the cave entrance. Given its rural setting, the most practical way to reach it is by car, using GPS navigation set to Pillarno, Castrillón. Since the site is privately owned with limited access, it's worth checking current directions and on-site signage before you set out.

When is the best time to visit?

The cave can be visited year-round, since its internal temperature doesn't follow the seasonal swings on the surface — a typical trait of karst caves. In practice, spring and summer tend to be the most convenient window, as longer days and milder weather outside make it easy to combine the visit with time along the Asturian coast. Because opening hours at this privately run site are limited, it's worth confirming the current schedule and ticket availability before arriving rather than showing up unannounced.

Frequently Asked Questions

Is Gruta de Arbedales open to the public? Yes, the cave is open to visitors as a private attraction, though access can be limited — check current opening hours and entry conditions before your visit.

How did the cave form? It's a karst formation in Devonian-era limestone, shaped over a long period by water action that carved out the chambers and built up the stalactite and stalagmite deposits.

When was the cave discovered? It was found by chance in 1963 during quarrying work at a nearby limestone quarry; the discovery is credited to Manuel del Busto.

Is it cold inside the cave? The interior holds a steady temperature of about 14°C throughout the year regardless of the weather outside, so bringing a light jacket even in summer is a good idea.