Agujero azul

Hundreds of garden eels sway above the sand like a slow living meadow. That's the first scene of the dive, after the descent from the Playa Chica pier stairs and a short swim across the submerged dune field. The eels retreat as you pass, and at the far edge of the colony the reef wall shows a dark opening at about 18 metres.

Inside, the collapsed lava tube is short and oriented. Keep the rock wall on your left, breathe high and hover, and within a minute the tunnel exit frames open blue water. The contrast is the moment of the dive. Behind you, sand and the tube; ahead, a cliff falling away into deep ocean. Caves and overhangs step down the wall to 30 metres, each one worth a slow torch pass. A small side cave shelters dense swarms of narval shrimp; resident groupers shadow the torchbeam, using the light to hunt. The return runs back along the shallower wall to the eel field for the safety stop.

"Blue hole" is a generic dive name used worldwide, and most blue holes are vertical sinkholes or long caves. Lanzarote's version is neither. It is a short collapsed lava-tube traversing the reef edge from a bright sandy zone into open cliff water, and the appeal is the staged sequence rather than a single feature. You cross a documented garden-eel field, pass through a real overhead, and emerge directly onto a deep volcanic wall, all from one shore entry. The 2011 biosphere reserve guide chose the editorial line "una ventana a las profundidades" — a window into the deep — and that frames the dive accurately: the tunnel is the window, and the dive is what's on the other side.

The grouper interaction is the other signature. Shine a torch into a cliff cave and resident dusky groupers move in around you, using your light to flush prey. Forum trip reports from regulars describe five large groupers feeding aggressively in the torchbeam at depth — an interaction the diver controls, not one that happens to you.

The tunnel is geological rather than human. Lanzarote sits on a chain of submerged Holocene volcanic features, and the reef-edge collapse that created Agujero Azul is one of many lava-tube remnants along the Puerto del Carmen coast. The site reached its current public profile through the 2011 Lanzarote Biosphere Reserve diving guide produced by SPEL and the Cabildo de Lanzarote — page 104 of the catalogue, dive 22 of 37. Most Puerto del Carmen centre pages still echo that guide's narrative spine. The Playa Chica nearshore was declared a Special Conservation Zone (ZEC, Natura 2000) in September 2011, the same year the guide was published; the designation is environmental and adds no diver permits or fees. The English alias "Blue Hole" is the form used by international operators serving the Puerto del Carmen tourist trade.

Bring a torch. The tunnel is short enough to see daylight at both ends, but the dive's payoff is the cave system along the cliff after the exit, where torchlight triggers the grouper hunting response and reveals the narval shrimp colony in the side cave.

Buoyancy discipline inside the tunnel is not optional. The space is tight enough that a single careless fin kick turns clear water into soup for everyone behind you. If you're not confident in confined spaces, a shallower variant of the dive that stays above the tunnel mouth and explores the eel field is a satisfying dive on its own.

The cliff face beyond exits past 30 metres, so plan gas and NDL around the deep portion and don't extend bottom time chasing one more cave. The local narcosis protocol is straightforward — slow descent, calm breathing, ascend a few metres if symptoms appear — and worth re-reading on briefing day. Watch for boat traffic on ascent near the Playa Chica pier, deploy an SMB on the safety stop, and arrive early at the small Playa Chica car park or use a centre with van transport.