El desierto

The first section crosses a shallow rocky area fringed with algae before dropping to a reef edge at roughly ten metres, where crevices, small arches, and volcanic pockets shelter moray eels and crustaceans. Beyond this edge, the terrain opens into a broad sand flat — and here the garden eels appear. Thousands of slender bodies sway in unison from the black volcanic sand. The colony covers the flat from edge to edge. Approach slowly; the colony retracts at the first sign of disturbance. Past the eel field, a circular stone reef and small underwater crater add structural relief, and groupers of notable size shadow divers through this section with an almost companionable persistence. For those with the certification and gas supply, a second reef edge at the far end descends steeply past 30 metres into deeper water where jacks and tuna hunt along the wall.

El Hierro's other signature dives are vertical: walls, pinnacles, lava tubes. El Desierto is horizontal. A flat expanse of volcanic black sand defines the site, and the garden eel colony across it is what no other reserve site replicates. Thousands of slender bodies rise in unison, forming one of the largest documented concentrations in European waters, present on every dive regardless of season. The contrast between the apparently barren sand flat and the density of life it supports gives the site both its name and its character. It also sits on the reserve's western passage for devil rays — occasional large visitors that add open-water scale to a dive that otherwise stays close to the bottom.

Garden eels are the main event, but they punish impatience — fin kicks near the colony send them underground in seconds. Neutral buoyancy and a slow, horizontal approach are essential for both observation and photography. The sand flat itself is not visually dramatic until the eels emerge, so trust the route and give it time. Beyond the eel field, watch your depth at the second reef edge where the wall drops steeply past 40 metres; agree on a maximum depth with your buddy before reaching it. The site sits inside the sheltered Mar de las Calmas. Current is mild and conditions are consistently manageable.