On one side there is a gently shelving stony beach with several fishermen's huts. The boats are often pulled up on to the stony beach. The bottom of the lagoon is also mostly pebbles and rocks and is fairly shallow. As you exit through the tunnel towards open sea, the floor drops away in a series of shelves to a depth of up to 35 metres on the outside. Jacques Cousteau said the Inland Sea was among his top ten dives .
On calm days fishing boats, known in Maltese as luzzijiet, can pass through the tunnel. Some of the boats are used to take visitors through the archway and then for a tour of the nearby cliffs and other sites, mainly to the Fungus Rock and another large natural arch in the cliffs called the Azure Window.