From south, Maen Piscar (dries 1.7m) is a major hazard on the chord between Rhoscolyn Head and Penrhyn Mawr. Give coastline 0.5 mile clearance from Rhoscolyn beacon until Trearddur opens, then turn in. From the north, go south of Penrhyn Mawr until chimney (127m. R.lts.) bears 055° before turning into anchorage.
Reefs extend half mile off headlands to north and south of Penrhos Bay. Maen Piscar (dries 1.7m) on chord between headlands. Extensive drying patch to north of main anchorage. Heavy mooring chains in Porth Diana (to south of TBYC) make anchoring impossible.
From north-west through north to south-east. Very exposed to south-westerly winds. Fairly good holding on sand and shingle. Pick up private mooring if possible.