The waters surrounding Monte Argentario are among the most pristine in the Mediterranean - a protected marine environment with exceptional visibility, thriving posidonia meadows and a remarkable diversity of marine life. Whether you're a certified scuba diver seeking dramatic underwater landscapes or a snorkeler looking for colourful fish in shallow coves, Argentario delivers unforgettable experiences beneath the surface.
Best Dive Sites
Cala del Gesso
The underwater world around Cala del Gesso is exceptional. The seabed drops away steeply from the shore, revealing granite boulders carpeted in colourful sponges and sea fans. Schools of sea bream, wrasse and damselfish are common, and patient divers may spot octopus, moray eels and even seahorses hiding among the rocks. Visibility regularly exceeds 20 metres, making it one of the finest shore-accessible dive sites in Tuscany. Snorkelers will enjoy the shallows too, where posidonia meadows host an abundance of small fish and invertebrates.
Argentarola Island
The tiny island of Argentarola, just off the western tip of Monte Argentario, is surrounded by some of the richest underwater terrain on the coast. Submerged caves, archways and vertical walls descend to depths of 40 metres and beyond. The site attracts larger pelagic species - barracuda, amberjack and occasionally dolphins pass through. This is an advanced dive site due to currents and depth, best explored with a local dive school. The underwater topography is dramatic and photogenic, making it a favourite among underwater photographers.
Isola Rossa
Located on the southern side of Argentario near Porto Ercole, Isola Rossa (Red Island) is a small rocky outcrop with excellent diving. The site features swim-throughs, overhangs and fields of red and yellow gorgonian fans. At moderate depths (15–25 metres) you'll encounter grouper, scorpionfish and nudibranchs. The relatively sheltered position makes it accessible on most days, and it is a popular choice for dive schools introducing clients to Argentario's underwater world.
The Nasuto Wreck
For wreck diving enthusiasts, the Nasuto is a cargo ship that sank near Argentario and now rests at around 30 metres depth. The wreck is well colonised by marine life and provides an atmospheric dive with good penetration opportunities for experienced divers. Several dive schools include the Nasuto in their regular excursion schedules.
Best Snorkeling Spots
You don't need scuba gear to enjoy Argentario's underwater beauty. The best snorkeling spots are found at the rocky coves where clear water meets the shore:
- Cala del Gesso - Shallow rocks teeming with fish, just wade in from the beach
- Cala Piccola - Turquoise water over a rocky seabed rich with marine life
- Le Cannelle - A sheltered cove with sandy patches and posidonia meadows
- Porto Ercole rocks - The rocky platforms south of the harbour offer easy snorkeling access
Bring your own mask and snorkel - rental is available but the quality varies. The best snorkeling is in the morning, when the water is calmest and the light penetrates deepest.
Dive Schools & Courses
Several professional dive centres operate around Argentario, offering everything from introductory discover scuba experiences to advanced certifications. Schools are based in Porto Santo Stefano and Porto Ercole, with daily boat excursions to the best sites. Expect to pay around €70–90 for a guided two-tank boat dive, or €250–350 for an Open Water certification course. Equipment rental is included in most packages. The dive season runs from May to October, with September offering the warmest water temperatures (around 24°C) and best visibility.
Marine Conservation
Argentario's waters benefit from their proximity to the Santuario dei Cetacei (Pelagos Sanctuary), an international marine protected area covering the Ligurian and Tyrrhenian seas. Several species of dolphin and whale are regularly sighted in deeper waters offshore. Divers and snorkelers are encouraged to respect the marine environment - avoid touching coral and posidonia, don't feed fish, and take any rubbish back to shore.
After a day exploring Argentario's underwater world, return to our apartment in Montiano - just 15 minutes from both Porto Santo Stefano and Porto Ercole - to rinse your gear, relax on the terrace and plan tomorrow's dive.
