The roof of Benagil's most photographed sea cave is not a roof at all — it is an eye, a circular collapse called an algar, opened by rainwater dissolving limestone from above long before the sea broke through from below. The coastline between Albufeira and Carvoeiro is built from Miocene limestone laid down when the Algarve lay beneath a warm shallow sea. Waves exploit its fault lines. Salt crystallises in the pores. Over millennia the cliff face has been carved into a lattice of arches, blowholes and roofless chambers, and the sand that fills them is the pale debris of the cliffs themselves. São Rafael, Praia da Coelha and Praia do Castelo each sit inside a bay that was once solid rock. An albufeira kayak cave tour follows that geology at water level, where the erosion is legible in a way it never is from the clifftop. The name Albufeira descends from the Arabic al-Buḥayra, the lagoon, a legacy of five centuries of Moorish rule that ended in 1249. Fishing sustained the town until the 1960s, when the first charter flights landed at Faro and the Algarve became one of Europe's most visited coastlines. The boats that once carried sardine nets now carry paddlers. Local operators running Albufeira sea cave kayaking tours work from beaches rather than marinas, which keeps groups small and launches quiet. Protection has followed popularity. Much of the shoreline falls within the Southwest Alentejo and Vicentine Coast framework of coastal safeguards, and the Benagil chamber itself has been regulated since 2024, with unaccompanied swimming and unsupervised landing restricted to protect both the rock and the people beneath it. Guided access is now the rule rather than a convenience, which is why every albufeira kayak cave tour tour departing this stretch of coast runs with a qualified skipper or paddle guide. What the water reveals is not one cave but a system. Pirate Cave and Monster Cave sit within paddling distance of Benagil. Praia da Marinha, with its double arch, marks the eastern edge of the classic route. Common dolphins and bottlenose pods feed offshore through the summer, and Cory's shearwaters nest in the cliff ledges above. Entry to the beaches themselves costs nothing — the coast is free, at 0 EUR — and the sea does the rest. Albufeira kayak cave tour departures exist because the geology is simply unreachable on foot.