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.

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.

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.

Punta Omo Morto is a reef and wall site in Ustica, Italy, characterised by large pyroclastic rock blocks along a slope. Divers typically explore between 20 and 30 metres, with an average depth of 25 metres. The site features colourful gorgonians and provides habitat for groupers. Marine life observed here includes bream, wrasses, Turkish wrasse, Cleaver wrasse, Mediterranean cardinalfish, painted comber, Madeira rockfish, hermit crabs, purple sea stars, fireworms, and mauve stingers. Nudibranchs such as Cratena slug and Mediterranean violet aeolid are also present. Access is by boat only, and divers should be aware of boat traffic and depth. Visibility reaches up to 40 metres, with mild currents.

Punta Falconiera is a diverse dive site on the eastern side of Ustica, Italy, offering a varied topography of walls, reefs, and caves. Accessible only by boat, the site features depths ranging from 10 to 42 metres, with an average depth of 24 metres. A notable cave is located at a depth of 20 metres. Divers should expect moderate currents and visibility between 15 and 30 metres. Water temperatures range from 15C to 20C. This site is suitable for intermediate divers and supports night diving. Due to the depth and overhead environments, divers must manage risks associated with nitrogen narcosis and sharp coral.

Grotta delle Cipree is a cave and reef site located off the coast of Ustica. Divers access this location by boat, with depths ranging between 18 and 23 metres. The site features an overhead environment that requires strict buoyancy control and adherence to cavern certification standards. Visibility is consistently high at 30 metres, and the area experiences mild currents. A halocline within the cave maintains a constant temperature, though ambient water temperatures vary from 15 to 23 degrees Celsius throughout the year. Guided tours are strongly recommended for first-time visitors to safely navigate the cave layout and swim-throughs.