Cala Chiai di Luna entered between Capo Bianco and Punta Fieno, 0. 8 mile SSE, has the shape of an amphitheatre. Much of the head of the bay is fronted by a narrow sandy beach fringed with rocks; behind it rise vertical cliffs of yellow rock with occasional dark strata. In the S part of the bay the cliffs drop at a narrow opening within which lies the entrance to a Roman tunnel easily seen from seaward. Anchorage can be obtained in depths of about 9 m, sand, 550 m NNE of Punta Fieno. At night Rotonda della Madonna Light is visible from the S side of Cala Chiai di Luna and may be used to approach the anchorage. An indication of the anchorage is provided when Punta della Guardia Light is obscured by the high ground N of it. Small vessels can anchor off a moderately high, conical rock which lies approximately 50 m off the head of the bay; stern ropes can be secured to the rock. Mariners should note that with winds from S or SSE the sea rounds Punta della Guardia and enters the bay. A SE wind is often accompanied by violent squalls which render the anchorage untenable.