Either Skomer Island or the mainland extremity of Wooltack Point at the western end of the Marloes Peninsula marks the southern limit of the bay whilst its northern limit is marked by Ramsey Island off St David's Head.
[1] The northern and southern shores of the bay are mainly rocky in nature, backed by cliffs up to 250 feet (76 m) high.
Its eastern shore comprises a series of large and small sandy beaches between rocky sections.
The geological exposures around the bay reveal great complexity with considerable folding and faulting of the strata.
Those in the north comprise a series of Precambrian and Cambrian age rocks of both sedimentary and igneous origin.