Baja Sardinia occupies a granite thumb on Sardinia's northeastern coast, where the Gallura shoreline fractures into a hundred wind-sculpted coves before dissolving into the protected waters of the La Maddalena Archipelago National Park. Established in 1994, the park spans seven major islands and sixty islets across 180 square kilometres of marine reserve, anchoring one of the Mediterranean's highest concentrations of Posidonia oceanica seagrass meadows and sheltering species from dusky grouper to loggerhead turtles. The bay's name derives from a 1960s resort village built by the Aga Khan's Costa Smeralda consortium, but the underwater topography predates human settlement by three hundred million years: pink granite plutons cooled beneath the surface during the Paleozoic, then weathered into the rounded boulders and submerged rock gardens visible today. Snorkeling Baja Sardinia tours depart from nearby Palau and Cannigione, targeting the archipelago's western approaches where depth contours drop gently from four to fifteen metres and visibility routinely exceeds twenty-five metres between May and October. La Maddalena's sheltered channels host damselfish, rainbow wrasse, and schools of salema porgy grazing the seagrass, while Tavolara's eastern cliffs—rising 565 metres sheer from the Tyrrhenian—create nutrient upwellings that draw pelagic visitors and support sponge colonies on vertical walls. Full-day sailings typically anchor at three to four sites: Spargi's Cala Corsara for sandy-bottomed shallows, Budelli's Spiaggia Rosa approach zone for granite boulder swim-throughs, and Mortorio's western shore where the seabed transitions to cobalt at twelve metres. Catamarans and motorized ribs depart between 09:00 and 10:00, returning by 17:00, with snorkel gear, wetsuits when requested, and onboard lunch included. The Tavolara Marine Protected Area, declared in 1997 and expanded in 2004, enforces seasonal mooring limits and prohibits spearfishing, allowing gorgonian fans and barrel sponges to colonize deeper granite outcrops. Summer water temperatures peak at 26°C in August, moderating to 22°C by late September when autumn light sharpens underwater contrast and reduces midday glare. Regional operators collaborate with park authorities on low-impact itineraries, rotating anchorage points to distribute pressure across fifty designated snorkel zones and limiting group sizes to maintain the quiet that once made these waters a refuge for Mediterranean monk seals—last sighted in the archipelago in 1973 but memorialized in island toponyms and folklore.