Porth Pant Gwyn (above) and Porth Bieg are essentially one long beach of sand and shingle on the Llŷn Peninsula's northern coast. Both beaches have mostly seaweed-covered rocks below the mid-tide point. Access to Porth Bieg (Grid Ref: SH254380) is from the coastal path north of Porth Towyn, which drops down to near beach level as it crosses a small stream.
About 400 yards further north, the coastal path crosses the Afon Mynachdy, where waterfalls drop onto the shore - this end of the beach being known as Porth Pant Gwyn and is a little more sandy. It's possible to scramble down to the beach at this point, but something more resemblant of a path can be found further east. The closest parking is as for Porth Towyn, at Towyn Farm.
The photos were taken around mid-tide.