Cueva del Infierno

Drop in close to the seaward entrance, finning into a rocky passage that opens to the sky above and to the sea on both ends. The chamber is shallow — ten metres at the deepest — and short enough that gas, not no-deco time, is the limit. Light comes down through the roof opening rather than from the boat above, which gives the swim-through its character: you watch sun shafts cut through suspended particles instead of staring into a torch beam. The walls are Paleozoic schist with pegmatite veins, the same metamorphic rock the rest of the cape is built from. There is room to hover and look up, then exit on the opposite side of the passage and use the remaining gas on the wall outside the cavern, where the cape's usual moray and octopus crevices are in reach.

The dive is sold on geometry and light, not on biology or scale. A roof opening makes this the cape's only named cavern an Open Water diver can swim through without cave training, with daylight visible from inside the whole way. The cave's name tracks a dawn effect — sunrise light turns the water inside a red glow that locals call a gate to hell — but that show is mainly for early kayakers and snorkellers. Boat divers see the cavern in its everyday state, which is enough on its own: a short overhead with a skylight, sitting at the easternmost point of mainland Spain, framed by Cap de Creus rock that is older than most of the Mediterranean coastline.

The dive itself is benign; the surface above it is the variable. Cape-tip exposure to Tramontana and easterly storms shuts boat access with little warning in any season, and operators routinely swap in alternative cape-area sites when conditions on top close the cave. Most divers reach Cueva del Infierno as the shorter second tank of a two-tank Cadaqués circuit rather than as a stand-alone trip — pair with Massa d'Or, Oliguera, or one of the other cape-tip caves to make the boat run worthwhile. Bring a torch for roof and crevice detail, deploy an SMB on ascent because the surface above is busy with kayaks and small boats in summer, and stay off the ceiling and bottom inside the chamber. Standard ID, certification card, logbook and a medical clearance no older than two years apply across the natural park.