SeaLogItaly · cave · intermediate
A drowned karst passage under Punta Giglio: stalactites that formed in air, the old sea-level line just inside the entrance, and a breathable air bell at the end.
Grotta delle Stalattiti is one of the submerged caves along the Punta Giglio cliff, on the eastern side of the Porto Conte bay near Alghero, and it is dived by boat. The entrance is at 7 m. Both Alghero Divers and Poseidon Diving Center describe the same shape inside: smooth, water-worn walls that read as an old watercourse, a horizontal passage of roughly fifty metres, a right-angle bend, and a chamber at the end holding a pocket of breathable air. Poseidon points out the line just inside the entrance that marks where the sea used to stand, and a single column-sized stalactite next to it.
What makes the cave worth the trip is that it is a land formation now underwater. The stalactites and stalagmites on the vault grew in air during the last glaciation, when the sea was far lower, and they are still there; there are more of them inside the air chamber. Alghero Divers is straightforward that the cave itself is thinly inhabited compared with the wall outside it, listing marbled electric ray, small crawfish and forkbeard as the occasional residents. The classic Mediterranean cave fauna is what turns up: Stenopus spinosus and Lysmata seticaudata shrimp, Galathea strigosa, cardinalfish, congers and the sponge-and-nudibranch pairing of Petrosia ficiformis with Peltodoris atromaculata are all recorded along this stretch of coast.
This is an overhead dive, and the shallow depth does not change that. Poseidon Diving Center, which runs it, states plainly that its cavern specialty course is what you need to explore the caves of Punta Giglio and Capo Caccia. The whole coast lies inside the Area Marina Protetta di Capo Caccia - Isola Piana: the Punta Giglio cliff face is Zone B, the park keeps its submerged caves on a separate list from its open-water dive points, and diving is done either with an authorised centre or on an individual authorisation obtained from the park office.
By boat from Alghero or Fertilia to the Punta Giglio cliff on the eastern side of Porto Conte. Alghero Divers, based at Fertilia, and Poseidon Diving Center both run the Punta Giglio cave circuit, which also includes Grotta dei Fantasmi, Grotta dei Cervi, Grotta del Pozzo and the Bramassa complex.
Access to the site runs through a local operator.
Inside the Area Marina Protetta di Capo Caccia - Isola Piana. The Punta Giglio cliff face falls in Zone B (general reserve). The park lists its submerged caves separately from its open-water dive points and treats them as an authorised activity; divers go either through a centre on the park's authorised list or on an individual authorisation applied for at the AMP office. Poseidon Diving Center states that a cavern specialty certification is what is needed for the Punta Giglio and Capo Caccia caves.
Individual (non-centre) divers apply to the Area Marina Protetta with the annual authorisation form; the park charges the request a 16 euro revenue stamp and a second 16 euro stamp on collection of the paper authorisation at the Casa Gioiosa office. Diving rules sit in the AMP's annual disciplinare attuativo, article 7 of which covers underwater activities.
A boat dive from Alghero or Fertilia onto the Punta Giglio cliff, inside the sheltered Porto Conte bay. Shallow throughout, with no ambient light past the entrance zone and a cave interior that Alghero Divers describes as sparsely populated compared with the wall outside.
On current: 7 m is the entrance depth, which is the only figure either operator publishes and the deepest point quoted for the cave; the passage runs roughly level and then rises to an air pocket, so the dive is shallow throughout. No source read for this page gives a visibility figure or a current for the site, so neither is set.
Shallow. Both Alghero Divers and Poseidon Diving Center put the entrance at 7 m, and that is the deepest figure either publishes for the site. The passage then runs roughly level for about fifty metres and rises at the end into a chamber with a pocket of air, so the whole dive stays within the first ten metres of water.
The depth is easy; the cave is not. Behind the entrance there is about fifty metres of unlit passage and a right-angle bend that cuts your view of the exit, which makes it an overhead dive whatever the depth reads. Poseidon Diving Center, which runs it, says a cavern specialty certification is what these Punta Giglio and Capo Caccia caves call for.
By boat, from Alghero or from Fertilia, onto the Punta Giglio cliff on the eastern side of the Porto Conte bay. Alghero Divers and Poseidon Diving Center both run this stretch, which strings together Grotta delle Stalattiti with Grotta dei Fantasmi, Grotta dei Cervi, Grotta del Pozzo and the Bramassa complex.
They formed in air. During the last glaciation the sea stood far lower than it does now and the cave was dry, so stalactites and stalagmites grew normally on its vault; the sea then rose and drowned them. Poseidon Diving Center points out the line just inside the entrance that marks the old water level, with a column-sized stalactite beside it, and there are more formations inside the terminal air chamber.
Not a great deal of fish. Alghero Divers is explicit that the cave is thinly populated compared with the wall outside, listing marbled electric ray, small crawfish and forkbeard as occasional residents. What you do get is the cave-dwelling invertebrate set recorded along this coast: Stenopus spinosus and Lysmata seticaudata shrimp, Galathea strigosa, cardinalfish, congers, and the sponge Petrosia ficiformis with its nudibranch Peltodoris atromaculata.
The site is inside the Area Marina Protetta di Capo Caccia - Isola Piana, and the Punta Giglio cliff face is Zone B. In practice you dive with one of the centres on the park's authorised list; individual divers can instead apply directly to the AMP with its annual authorisation form, which carries a 16 euro revenue stamp on the request and a second on collection at the Casa Gioiosa office.
No. The entrance is 7 m down on a cliff face reached by boat, and everything the cave is known for lies behind fifty metres of dark passage. From the surface there is nothing to see, and this is not a site to freedive either.
| Species | How often | Records |
|---|---|---|
| Stenopus spinosus | rare | 4 |
| Spongia (Spongia) lamella | rare | 4 |
| Palaemon serratus | rare | 3 |
| Thorogobius ephippiatus | rare | 3 |
| Acanthella acuta | rare | 3 |
| Octopus vulgaris | rare | 3 |
| Felimare tricolor | rare | 3 |
| Halocynthia papillosa | rare | 2 |
| Galathea strigosa | rare | 2 |
| Lysmata seticaudata | rare | 2 |
| Hacelia attenuata | rare | 2 |
| Echinaster (Echinaster) sepositus | rare | 2 |
| Conger conger | rare | 2 |
| Coris julis | rare | 2 |
| Labrus merula | rare | 2 |
| Serranus cabrilla | rare | 2 |
| Diplodus puntazzo | rare | 2 |
| Diplodus sargus | rare | 2 |
| Sarpa salpa | rare | 2 |
| Tripterygion delaisi | rare | 2 |
| Dysidea fragilis | rare | 2 |
| Luria lurida | rare | 2 |
| Lithophaga lithophaga | rare | 2 |
| Petrosia (Petrosia) ficiformis | rare | 2 |
| Apogon imberbis | rare | 2 |
| Scorpaena maderensis | rare | 2 |
| Peltodoris atromaculata | rare | 2 |
| Felimare orsinii | rare | 2 |
| Edmundsella pedata | rare | 2 |
| Pseudodistoma cyrnusense | rare | 1 |
| Dromia personata | rare | 1 |
| Marthasterias glacialis | rare | 1 |
| Paracentrotus lividus | rare | 1 |
| Gobius vittatus | rare | 1 |
| Chromis chromis | rare | 1 |
| Epinephelus costae | rare | 1 |
| Diplodus vulgaris | rare | 1 |
| Tripterygion melanurus | rare | 1 |
| Pleraplysilla spinifera | rare | 1 |
| Ircinia oros | rare | 1 |
| Agelas oroides | rare | 1 |
| Dictyonella incisa | rare | 1 |
| Dendroxea lenis | rare | 1 |
| Haliclona (Halichoclona) fulva | rare | 1 |
| Crambe crambe | rare | 1 |
| Phorbas tenacior | rare | 1 |
| Spirastrella cunctatrix | rare | 1 |
| Pelagia noctiluca | rare | 1 |
| Bittium latreillii | rare | 1 |
| Flabellina affinis | rare | 1 |
| Haliotis tuberculata | rare | 1 |
| Hexaplex trunculus | rare | 1 |
| Labrus mixtus | rare | 1 |
| Sarcotragus fasciculatus | rare | 1 |
| Sarcotragus spinosulus | rare | 1 |
| Haliclona (Reniera) mediterranea | rare | 1 |
| Euthria cornea | rare | 1 |
| Symphodus mediterraneus | rare | 1 |
| Symphodus ocellatus | rare | 1 |
| Symphodus rostratus | rare | 1 |
A shallow, unlit karst cave under Punta Giglio — white alabaster, heavy silt, and the only cave in the Alghero park that a diver may not enter without a full cave certification.
A siphon under Punta Giglio leads into an air chamber where the bones and antlers of extinct Sardinian dwarf deer are set in the calcite.
A hundred metres of shallow collapse caves, canyons and window exits inside Porto Conte, no deeper than 8 m, dived when the sea outside is too rough for the headlands.
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