[1] Starting in the north, at Ness Head, the bay is bounded by Freswick Bay, and overlooked by Skirza Head, the bay proper sweeps south in a long elliptical curve, before sweeping east to pass the remains Castle Sinclair[2] and terminating at Noss Head Lighthouse.

[3] Sinclairs Bay has two primary geological features.

Starting at the coastal village of Keiss, running northeast, a stony beach and coastal crags, become cliffs that are increasingly sheer the further north.

South of Keiss, the cliffs even out in a large white sandy beach, called Keiss Beach, forming large Dunes of Reiss Beach further south.

At Ackergill Tower, the beach again becomes stony and eventually forms into a series of cliffs and crags, further east.