Nereo Cave
Capo Carbonara · Italy
The largest underwater cave in the Mediterranean, cut into the limestone cliffs of Capo Caccia just north of Neptune's Grotto near Alghero. A main tunnel runs roughly 300 metres through the headland, linked by around ten arches and side passages between the surface and 35 metres. Walls and ceilings are crusted with red coral (Corallium rubrum) and clusters of yellow Leptopsammia pruvoti, while dusky groupers, congers, Mediterranean morays and spiny lobsters shelter in the dark recesses. Summer visibility regularly tops 30 metres.
Conditions
Depth
10 to 35 m
Advanced depths
Current
Usually gentle
Can pick up on the edge
Visibility
25 to 35 m
Clearest in the calm season
Water
13 to 26°C
7mm wetsuit
Month by month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Water (°C) | 14 | 13 | 13 | 14 | 16 | 19 | 22 | 24 | 22 | 19 | 17 | 15 |
| Vis (m) | 12 | 12 | 15 | 15 | 18 | 20 | 25 | 25 | 20 | 18 | 15 | 12 |
| Current | Gentle | Gentle | Gentle | Gentle | Gentle | Gentle | Gentle | Gentle | Gentle | Gentle | Gentle | Gentle |
Your chances of seeing each animal
Red coral
Last confirmed May 15, 2026 · 130 records
Almost always
Nearly every dive
Dusky grouper
Last confirmed May 21, 2025 · 1 records
Likely
About 6 in 10 dives
European conger
Last confirmed May 25, 2026 · 2 records
Likely
About 6 in 10 dives
Mediterranean moray
Last confirmed May 20, 2025 · 1 records
Likely
About 6 in 10 dives
Yellow cave coral
Expected
Known here, not yet in recent logs
European spiny lobster
Expected
Known here, not yet in recent logs
Gear