Spiaggia dei Pozzarelli in Porto Ercole is a reef site offering depths between 2 and 15 metres, with an average of 7 metres. Accessible by both shore and boat, the site features a rocky seabed suitable for intermediate divers and snorkellers. Visibility typically ranges from 10 to 25 metres, though conditions vary. Marine life recorded at the site includes wrasses, bream, crabs, and hermit crabs. Divers may also encounter Mediterranean moray, white-spotted octopus, common octopus, European common cuttlefish, Turkish wrasse, cleaner shrimp, fried egg jellyfish, scorpionfish, conger eel, and Cratena slug. Be aware of jellyfish as a potential hazard when diving or snorkelling in this area.

Torre del Campese is located at the northern end of Campese Bay near Isola del Giglio. This site features a combination of natural reef and artificial structures formed by the rocky foundations of the historic Medicean Tower. Snorkellers can access the water directly from the shore. Depths range from 1 to 40 metres, though the average depth is 1 metre, making it suitable for beginners. Conditions vary, with visibility typically between 5 and 25 metres and mild currents. Hazards include sea urchins, sharp coral, and surge. Facilities available at the site include parking, showers, and gear storage.

Cala dell'Allume is a heart-shaped cove located on the west coast of Isola del Giglio. The site features a rugged seabed defined by mineral-rich rocks from a former pyrite mine, creating numerous crevices and caves. Water temperatures range from 14C to 26C, with underwater springs occasionally creating cold spots. Access is available from both shore and boat. Due to the presence of sharp coral and potential for entanglement, this site is recommended for intermediate snorkellers. Species recorded around this area include wrasses, Mediterranean moray, European common cuttlefish, and various octopus species, though these are not confirmed sightings at this specific location.

Cala del Corvo is a cove on the west coast of Porto Ercole featuring a sea cave with a small internal beach. The site consists of underwater walls covered in sponges and corals, reaching depths of up to 40 metres with an average of 20 metres. Access is by boat only, and the site is suitable for advanced divers due to strong currents. Visibility ranges from 10 to 30 metres. Species recorded around this area include wrasses, Mediterranean moray, common octopus, and various nudibranchs. The site is also rated highly for snorkelling. Water temperatures fluctuate between 14C and 18C throughout the year.

Allume is a marine site located 500 metres off the coast of Isola del Giglio, featuring a combination of reef and cave topography. The site ranges in depth from 10 to 30 metres, with an average depth of 15 metres. Access is strictly by boat, and divers should be prepared for moderate currents that can strengthen without warning. The presence of an overhead environment within the cave system requires careful buoyancy control and air management. Visibility typically spans 10 to 30 metres. Water temperatures fluctuate between 14 and 20 degrees Celsius, necessitating a 5mm wetsuit in warmer months and a 7mm suit during the cooler periods from autumn through spring.

Secca dei Pignocchi is an offshore reef and pinnacle system located near Porto Ercole. The site features a topography that rises to within 2 metres of the surface, with depths extending down to 35 metres and an average depth of 20 metres. Access is strictly by boat. Divers and snorkellers should be aware of strong currents present at this location. Water temperatures range between 14C and 19C throughout the year, with conditions in April reaching approximately 15.4C, which poses a risk of hypothermia during prolonged exposure. The site is suited for intermediate level divers due to the current and depth profile.

Punta Della Nave near Porto Ercole is a marine site featuring a combination of reef, wall, and pinnacle topography. Divers typically encounter depths averaging 21 metres. Access to this site is exclusively by boat. Conditions are variable, with visibility generally ranging between 15 and 25 metres and moderate currents present. Water temperatures fluctuate throughout the year, ranging from 14C in March to 23C in September. Due to the depth and current conditions, this site is suited for intermediate divers. Divers should be aware of sharp coral present in the area.

Secca dei Subielli is a boat-access reef and wall site located 1000 metres from the shore near Porto Ercole. The topography features a combination of reef and wall sections, offering intermediate divers varied terrain between 10 and 30 metres depth, with an average depth of 20 metres. Conditions are generally manageable with mild currents and visibility ranging from 10 to 25 metres. Water temperatures fluctuate between 14C and 20C, necessitating a 5mm wetsuit for most of the year. Species recorded around this area include wrasses, Mediterranean moray, European common cuttlefish, and various octopus species. Typical dive times are approximately 45 minutes.