Off Ponza, Secca di Silverio is a deep offshore shoal with a steep eastern wall and a technical boat-dive profile. The approach is by boat from the island's north-east side, and the terrain is best handled with calm water, a clean briefing, and conservative gas and pickup planning rather than a casual shore-style drop-in. It suits experienced CCR or advanced divers, with john dory, large scorpionfish, lobsters, and red coral among the main draws.