Sassone is a reef site located in Villasimius, Italy, featuring a large stone formation that rises from a sandy bottom. The site is well suited for beginners and trainee divers, offering depths ranging from 5 to 18 metres with an average depth of 14 metres. Access to the site is by boat only. Divers can expect mild currents and visibility between 15 and 30 metres. Water temperatures fluctuate throughout the year, ranging from 15C in winter to 24C in September. Hazards at this location include boat traffic, sea urchins, and sharp coral. Typical dives at this site last approximately 45 minutes.

The Isonzo is an armed cargo ship sunk during the Second World War, resting at depths between 40 and 57 metres. The wreck lies on its side, with the upper sections reaching up to 40 metres. Due to the significant depth and potential for strong currents, this site is strictly for advanced divers. Visibility typically ranges from 15 to 30 metres. Divers must be prepared for decompression requirements and the risks associated with overhead environments and nitrogen narcosis. Access is exclusively by boat. Species recorded around this area include wrasses, bream, European parrotfish, grey triggerfish, painted comber, castagnole, white seabream, striped red mullet, salema porgy, and various snails.

Genn'e Mari is a reef and pinnacle site located near Villasimius, Italy. The topography consists of a shoal that begins at a depth of 15 metres and descends to 35 metres. Access to the site is by boat only. Due to the presence of moderate to strong currents, this site is suited for intermediate divers. Water temperatures range from 15C to 19C throughout the year. Species recorded around this area include wrasses, Turkish wrasse, European parrotfish, grey triggerfish, two-banded seabream, bream, striped red mullet, white seabream, painted comber, castagnole, salema porgy, and snails. Facilities available at the nearby dive shop include parking, toilets, showers, changing rooms, and a cafe.

Mari Pintau in Villasimius is a coastal site featuring a smooth pebble entry that transitions into a sandy bottom. The site consists of a reef and an artificial reef, with a submerged anchor located on the right side. Depths range from 2 to 10 metres, with an average of 4 metres, making it suitable for beginners. Conditions include mild currents and potential surf. Facilities available at the site include parking, toilets, showers, and a cafe. Guided tours are also available for those visiting the area.

Cala Regina is a rocky cove located 25km east of Cagliari, distinguished by a prominent Spanish watchtower overlooking the site. The seabed consists of rocky formations that reach depths between 2m and 15m, with an average depth of 7m. This shore-entry site is suitable for intermediate divers and offers visibility ranging from 10m to 25m. Currents are generally mild, though divers should be aware of sea urchins present in the area. With a 4/5 snorkel rating, the site is also accessible for surface exploration. Parking is available near the cove, and typical dives last approximately 60 minutes.

Secca di Santa Caterina is a complex site featuring a reef, pinnacle, and cave system located 2000 metres off the coast of Villasimius. The site is suitable for intermediate divers, with depths ranging from 12 to 38 metres and an average depth of 15 metres. Access is by boat only. Divers encounter mild currents and visibility typically between 15 and 30 metres. Water temperatures fluctuate between 15C and 19C throughout the year. Species recorded around this area include European common cuttlefish, Mediterranean moray, common octopus, Turkish wrasse, European parrotfish, various bream species, painted comber, tompot blenny, and castagnole. Hazards include sharp coral and the potential for strong currents.

Santa Caterina is a pinnacle and reef site located 1500 metres offshore in the Capo Carbonara Marine Protected Area near Villasimius. The site features a varied topography starting at 15 metres and descending to 40 metres, with an average depth of 25 metres. Access is strictly by boat. Divers should be prepared for mild to strong currents, which require intermediate skill levels. Visibility at the site ranges from 10 to 30 metres. Water temperatures remain between 15C and 18C throughout the year. Typical dives last approximately 45 minutes. Facilities including air fills, equipment rental, and boat charters are available locally.

The Romagna is a Second World War tanker wreck located off the coast of Villasimius, Italy. Sunk by a floating mine, the vessel remains largely intact with the deck resting at 30 metres and the site reaching depths of 42 metres. Divers can explore the structure, including the propeller and rudder area, where the 1.8-metre long propeller blades are a notable construction feature. Due to the depth and strong currents, this site is strictly for advanced divers. Access is by boat only, as the wreck lies over 22 kilometres from the shore. The environment supports a variety of Mediterranean reef fish and invertebrates typical of this deep-water habitat.