Grotta Utopia

A sea-entered cave below high cliffs in the Gulf of Orosei, reached by a 30 to 40 minute boat ride from Cala Gonone. A triangular entrance shaft drops to 28 m into a large, deepening system reported at more than 7 km and explored to 120 m.

ProTec Sardinia describes the Utopia as reached by boat to a point where cliffs rise up to 400 m from the sea. Divers descend to about 13 m, where a triangular entrance in the rocks drops to 28 m; at the bottom of this shaft a very large cave system opens, first running parallel to the cliffs and then heading inland, growing larger and deeper.

According to the same provider, the cave was discovered and systematically explored by the German HFGOK group in the late 1990s to 4.2 km. In 2013 Rick Stanton and a local explorer extended Markus Schafheutle's line from 102 m to 120 m, and the provider gives the current size as more than 7 km. A 2023 Undercurrent reader report describes a guided dive to about 32 m that followed the guideline into the large opening.

The provider describes long decompression with air and recommends different gases; this is a cave for experienced, qualified cave divers.

A large, roughly circular flooded tunnel system behind a deep entrance shaft, increasing in depth inland.