El Hierro

Dive conservatively. El Bajon and other current-fed sites can exceed the comfort level of newly certified divers, and walls continue far below recreational limits. Carry and know how to use an SMB, stay close enough to your guide for blue-water ascent control, monitor gas carefully, and avoid pushing no-decompression limits. For freediving, never dive alone, use trained buddy protocols, and arrange proper surface cover. For snorkeling, treat lava pools as ocean entries and skip them when swell washes over the rim.

For emergencies, call 112. El Hierro has public hospital care in Valverde, but suspected decompression illness should be handled as an emergency requiring oxygen, medical assessment, and possible evacuation to a hyperbaric facility on another island. Carry dive accident insurance, keep your operator's emergency plan handy, and do not drive yourself across the island while symptomatic after diving.

The reserve system restricts fishing, extraction, anchoring, diving locations, and activities in integral or restricted areas. Divers and snorkelers should maintain buoyancy, avoid gloves unless needed for exposure protection, keep fins off the bottom, never feed or chase wildlife, and report injured protected species or pollution to local authorities. The proposed Mar de Las Calmas national park process adds further reason to follow the most conservative local guidance.