The Ligurian Coast is a land-based, day-boat destination built around three protected marine areas. Portofino and Camogli deliver the signature experience: coralligenous walls, red gorgonians, red coral, the current-swept Secca dell'Isuela, and the shallow Cristo degli Abissi in San Fruttuoso. Cinque Terre adds park-designated underwater itineraries beside its five cliff villages, while Bergeggi offers a compact western circuit of walls, boulder fields, small caves, Posidonia, and schooling fish. Water is distinctly seasonal, from roughly 12°C to 14°C in winter around Portofino to about 24°C to 26°C in late summer. Scuba can run year-round, but snorkeling, freediving, ferries, and the easiest mixed itineraries favor May through October. Plan at least two bases, use authorized operators inside the reserves, and keep enough flexibility for swell, current, and marine-park site substitutions.