Grotta dei Gamberi is a complex marine site off the coast of Ustica, Italy, characterised by a dramatic wall and drop-off that descends from the surface to 45 metres. The topography features arches, large rocks, and a notable cave located at a depth of 40 metres. Due to the depth and the overhead environment of the cave, this site is strictly for advanced divers. Access is by boat only, with typical dives lasting 40 minutes. Divers encounter mild currents and visibility consistently reaching 30 metres. Water temperatures range from 15C to 20C throughout the year. Hazards include the significant depth, potential for nitrogen narcosis, and the overhead cave environment.

Grotta della Pastizza is a versatile site located 500 metres off the coast of Ustica, Italy. The topography consists of a wall and a cave system featuring two internal air pockets. The cave interior houses a statue of S. Bartolo, the patron saint of the island. With an average depth of 10 metres and a range of 8 to 12 metres, the site is suitable for beginners and offers a 4/5 rating for snorkelling. Access is by boat, and the site experiences mild currents with visibility ranging from 10 to 30 metres. Night diving is permitted, and guided tours are available through local dive shops.

Grotta Totò is a technical cave dive located off the coast of Ustica, Italy. The site features an overhead environment at depths ranging from 10 to 18 metres, with an average depth of 13 metres. Access is exclusively by boat. Divers must maintain strict buoyancy control and carry redundant lighting, as the cave interior presents limited light and no direct ascent options. Conditions are generally manageable with mild currents at the entrance. Water temperatures fluctuate between 15C and 25C throughout the year. Proper gas management and adherence to cave diving certification limits are essential for this dive.

Grotta delle Stalattiti in Ustica is an expert-level cave dive featuring significant geological formations. Divers access the site by boat to explore chambers containing stalactites and stalagmites, including a large formation known as The Palm Tree. The site involves an overhead environment where the entrance may be lost from view within the tunnel system. Depths range from 14 to 20 metres, with an average of 12 metres. Conditions include mild currents and water temperatures varying between 15C and 25C. Marine life recorded at the site includes bream, wrasses, European parrotfish, and various invertebrates such as the Mediterranean violet aeolid, Cratena slug, and purple sea star.

Grotta Azzurra in Ustica is a marine cave and reef site accessible by boat, located 500 metres from the shore. The site features a large sea cave where sunlight creates a distinct blue glow within the water. Snorkellers can explore the interior of the cave and the surrounding volcanic walls. Conditions are generally suitable for beginners, with mild currents and depths ranging from 5 to 25 metres, averaging 10 metres. Visibility varies between 6 and 25 metres. Water temperatures fluctuate throughout the year, ranging from 15C in winter to 28C in August. Hazards at this site include sea urchins and sharp coral.

Sutta zà Lisa is a boat-access site off Ustica, Italy, featuring a diverse underwater landscape of reef, wall, cave, and canyon formations. Divers typically explore between 10 and 30 metres, with an average depth of 20 metres. The site is suited to intermediate divers, offering a varied topography that remains manageable due to mild currents. Visibility can be variable, so local checks are recommended before diving. Water temperatures fluctuate between 15C and 22C throughout the year, requiring careful selection of exposure protection. Species recorded around this area include various wrasses, groupers, Mediterranean moray, common octopus, and several species of nudibranchs.

Punta San Paolo in Ustica offers a diverse underwater landscape featuring a reef, canyon, drop-off, and seagrass beds. The site is notable for La Spaccazza, a deep canyon that cuts through the cliff. Depths range from 8 to 30 metres, with an average of 18 metres. Access is by boat, and the site is suitable for beginners. Conditions include mild currents and visibility ranging from 15 to 30 metres. Water temperatures fluctuate between 15C and 28C throughout the year. Hazards to be aware of include boat traffic, jellyfish, sea urchins, and sharp coral. Guided tours, equipment rental, and air fills are available locally.

Sutta zia Lisa in Ustica, Italy, offers a diverse underwater landscape featuring a steep vertical wall, caves, canyons, and pinnacles. The site ranges in depth from 3 to 30 metres, with an average depth of 20 metres. Divers can explore fissures and boulder formations throughout the area. Access to this site is by boat only. Conditions are generally stable with mild currents and visibility ranging between 15 and 40 metres. Water temperatures fluctuate seasonally, reaching a high of 22C in October and a low of 15C during the winter months. This site is suitable for intermediate divers, with typical dive times lasting approximately 50 minutes.