Grotta Su Marmuri in Ulassai: How to Visit
Millennia-old stalactites, a constant 10°C year-round, and 850 metres of underground wonders: the complete guide to visiting the Grotta Su Marmuri in Ulassai.
A few kilometres from Ulassai, hidden within the limestone walls of the Ogliastrian plateaus, lies one of the most spectacular karst systems in Sardinia. The Grotta Su Marmuri — "the marble" in the local dialect — is a world apart: a constant temperature of 10°C year-round, millennia-old limestone formations, absolute silence.
What Is Su Marmuri
The cave extends for 850 metres of walkable passage, with a series of interconnected chambers reaching up to 60 metres in height. It is an active karst system: water continues to flow and formations continue to grow, albeit slowly (1 mm every 10–15 years).
Discovered by local shepherds in the nineteenth century, it was systematically explored in the 1950s–60s and opened to tourism in the 1980s. Today it is managed by the Municipality of Ulassai and is one of the most visited show caves in eastern Sardinia.
The Main Chambers
The Entrance Hall The route begins with a gradual descent. Temperature drops rapidly from the 20–25°C outside to the cave's 10°C. Humidity exceeds 90%.
The Stalactite Hall The heart of the cave. Thousands of stalactites of varying sizes hang from the limestone ceiling, some reaching up to 3 metres in length. Some formations are millions of years old.
Stalactites grow downwards, anchored to the ceiling. Stalagmites grow upwards from the floor. When they meet, they form columns — the most impressive formations in the cave.
The Lake Hall An underground lake of perfectly clear water occupies part of the floor. The water, filtered through limestone for centuries, has extreme purity. The formations above are reflected on its surface.
The Hall of Wonders
The final chamber is the largest: 60 metres high, it houses the most spectacular formations. The lighting has been designed to bring out the natural colours of the limestone — from ivory to pink, ochre to grey.
Practical Information
Tickets and Opening Hours - Summer (June–September): open daily, 9:00–12:00 and 15:00–18:00 - Off-season: weekends and public holidays only, or by appointment for groups - Full-price ticket: €10 - Reduced (children 6–14, over 65, students): €6 - Children under 6: free - Group bookings (10+ people): +39 0782 787220 (Municipality of Ulassai)
How to Get There The cave is reached from Ulassai by following the road signs (brown tourist signs). It is approximately 3 km from the village centre. Free parking at the entrance.
What to Wear
Despite the warm temperatures outside, the cave is always cold inside. Always bring:
- A fleece or light jacket
- Closed-toe shoes with non-slip soles
- In summer, you may want a layer you can remove on the way out
The floor is wet in places — open shoes or sandals are not recommended.
The Guided Tour
The visit is exclusively guided: independent access to the cave is not permitted. Guides are locally trained and know every formation. The standard duration is 60–75 minutes.
Guides speak Italian and, by prior arrangement, can conduct tours in English or Spanish.
Combining Su Marmuri with Ulassai
The cave pairs perfectly with Ulassai's other attractions:
- Morning: Stazione dell'Arte and the historic centre with Maria Lai's murals
- Lunch: A local restaurant (Ogliastrian cuisine is excellent: culurgiones, roast suckling pig, seadas)
- Afternoon: Visit to Grotta Su Marmuri
- Sunset: Viewpoint over the limestone plateaus
A full, unhurried day to discover one of Ogliastra's most original villages.
