Neptune's Grotto

Neptune’s Grotto (Grotta di Nettuno) is a coastal karst sea cave at Capo Caccia near Alghero on Sardinia’s northwest coast. It is one of the island’s best-known show caves and is notable for its large chambers and marine-access features.

The site features a large main cavern with extensive stalactite and stalagmite formations and an inland saltwater lake that is included on guided visits. Tours are typically timed and visitors enter either by boat when sea conditions allow or on foot via the coastal staircase.

The cave is a natural karst formation shaped by marine erosion and dissolution of limestone over long periods. It has been visited and mapped since the 18th and 19th centuries and developed for tourism with guided routes and safety works in modern times.

Situated on the cliffs of Capo Caccia near the town of Alghero in northwest Sardinia, the grotto sits at sea level on the Mediterranean coast and is reached from Alghero by short coastal drives and boat trips.

• Access options: Access is by guided tours; visitors can reach the grotto either by boat from nearby harbours or by descending the cliff staircase.
• Notable interior features: The cave contains an inland saltwater lake and extensive stalactite and stalagmite formations, reached on timed tours.

What to See #

• Escala del Cabirol: A cliff staircase of roughly 654 steps that links the plateau of Capo Caccia to the cave entrance and is the main pedestrian access route when sea conditions prevent boat landings.
• Main cavern and saltwater lake: A large sea cave chamber with stalactites and stalagmites and an inland saltwater lake that can be reached on guided tours.
• Sea access and landing point: Boat landing area on the coastal face of Capo Caccia used by tour operators from nearby ports when sea conditions allow.