Inland Sea (Dwejra)

A short surface swim crosses the lagoon before the tunnel even starts, flat and sheltered regardless of what the open sea outside is doing. Divers descend at the tunnel mouth and the light changes almost immediately: walls close to eye level carry sponges and cup corals, with cardinalfish sheltering in crevices within torch range. The tunnel narrows a little and deepens gradually, dropping from a few metres inside the lagoon to around 25-26 metres by the time it reaches the open sea. Nothing about the descent feels sudden. At the far end, the passage gives way abruptly to open water and a vertical wall, a genuine change of scene after several unhurried minutes underground. From there most divers choose a direction: left toward the Blue Hole and the collapsed Azure Window boulder field, or right toward a livelier reef and a scatter of separate caves and fissures. Either way, the return usually means the same tunnel again, torches on, cardinalfish and nudibranchs picked out one more time on the way back to the lagoon.

Length is what sets this tunnel apart from anything else nearby. At somewhere between 70 and 90 metres, it's a long transit by cavern-diving standards, but wide, mostly lit by daylight, and shared daily with tourist boats running the same route on the surface. That combination makes it feel less like an overhead-environment challenge and more like a corridor between two different seas. It also serves as the standard opening leg of Gozo's signature combined dive: swim the tunnel, pick up the wall, cross the rubble where the Azure Window used to stand, and surface inside the Blue Hole's own shaft, a route visiting divers ask for by name. A story that Jacques Cousteau once rated this among his personal favourite dive sites circulates widely on tourism pages. No original interview or publication carrying that claim has turned up in research for this entry, so it's best treated as popular lore rather than history.

Boats use this tunnel too, running tourist trips through the lagoon in season, so surfacing mid-transit is not an option here. Stay close to the tunnel walls, and if an engine gets loud, head down rather than up. A torch earns its place quickly. It turns the sponges and cup corals from grey shapes into colour, and it's usually the only way to spot the nudibranchs tucked into smaller crevices. The shore entry itself, a slipway over loose pebbles, can be slippery once you're fully kitted, so take it slowly. Once through the tunnel, the choice between the two directions along the wall is easy to lose track of without a compass, so plan and hold a heading before you commit either way. Planning to push on toward the Blue Hole instead of turning back? Agree the gas reserve in advance. The combined route runs long: around 80 minutes bottom time is typical for an experienced diver covering the whole circuit.