Tubo de Garachico

The boat drops you at a tunnel mouth that opens with a vertical descent to around 20 metres, where the passage makes a hard 90-degree turn and goes horizontal. From there it widens steadily, a single unbroken corridor through solidified lava with no side branches to lose track of. Slipper lobsters and the larger Canary lobster shelter in the cracks along the way, easy to miss without a torch trained on the walls. The tunnel runs for roughly 150 metres before opening into a wide chamber, where a basalt arch called Angel Wings frames the exit. One route in, one route out. Currents on the approach are the real variable, not the tunnel itself.

At 150 metres, this single-pathway lava tunnel is one of the deepest caves available for recreational diving in the Canary Islands, cut through rock laid down when the Trevejo volcano buried much of old Garachico town in 1706. What sets it apart from the shorter tunnel and chimney dives elsewhere on this coast is scale combined with structure: one continuous passage, deep enough to demand real certification, but simple enough in layout that getting lost isn't the risk. The current is.

Check sea conditions before you commit; strong current is a genuine, repeatedly flagged hazard here, and boat traffic adds another layer to manage on the surface. Bring a torch without question, plus a helmet given the overhead environment, and dress for cold: a drysuit or thick semi-dry in winter, 5mm in summer. Nitrox is worth arranging if your operator offers it, since it buys useful bottom time on the deeper approach to the tunnel mouth.