The site is characterized by a meadow of Posidonia oceanica, a priority habitat established on sand and/or ‘matte’. There are also many patches of Cymodocea. Pinna nobilis, which is a vulnerable and endangered species in Liguria, is also present in the site.
The Posidonia meadow is morphologically highly diversified, with coralligenous formations dominated by various species of Gorgonia. Two specimens of false black coral and numerous specimens of sponge trees have been found. Between Oneglia and Andora, the seabedsare characterized by fine sands with seagrass meadows, while near the rocky promontories with blocks and landslides, there are typical littoral algal communities on hard substrates.