For roughly a century, a single family on Tavolara Island claimed the title of royalty, and the graves of the self-styled Kingdom of Tavolara still sit in a small cemetery above the eastern shore. The island itself is a limestone massif nearly 6 kilometres long, rising to 565 metres at Monte Cannone, tilted out of the Tyrrhenian Sea like a fragment of a larger mountain range that the water never finished covering. Geologically it is an outlier. The surrounding coast of Gallura is granite — coarse, pink, weathered into rounded forms — while Tavolara is pale Mesozoic limestone, sheer on its northern face and terraced on the south. That contrast is visible underwater as much as above it. A tavolara snorkeling tour crosses from granite boulder fields near the Porto San Paolo shoreline into limestone shelves and sand channels within a few hundred metres, and the change in substrate changes what grows there. Since 1997 the waters have been administered as the Marine Protected Area of Tavolara Punta Coda Cavallo, covering some 15,000 hectares across three zones of graded protection. The reserve exists largely for Posidonia oceanica, the endemic Mediterranean seagrass whose meadows here are among the healthiest in the western basin. Posidonia stabilises sediment, oxygenates the water column and shelters juvenile fish; a single meadow can be thousands of years old. Around it live dusky groupers, salema, sea bream, the occasional loggerhead turtle, and the protected fan mussel Pinna nobilis, which has collapsed elsewhere in the Mediterranean and survives in pockets here. Neighbouring Molara, a smaller granite island to the south, adds a second character to the archipelago entirely — softer, lower, ringed with shallows. Entry to the island and the marine protected area is free at 0 EUR, with boat tour costs applying separately. That arrangement matters to the way the archipelago is used: the reserve is not a gated site but a working sea, shared with the fishermen of Loiri Porto San Paolo whose cooperative predates the park. Access to the island runs 08:00–20:00 daily. Much of Tavolara remains closed. The eastern third is a NATO military zone, off limits since the Cold War, which has left the interior largely unwalked and its endemic plants undisturbed. What visitors see on a Tavolara Island boat and snorkeling tour is therefore a deliberately partial view — the western beaches, the southern shallows, the vertical northern wall dropping into deep blue. Sardinia's marine protected areas are numerous, but few compress so much contrast into so little water, which is why tavolara snorkeling tour tours have become the standard way to read this coastline.