Trefor's small harbour was once used for exporting granite quarried in the nearby Yr Eifl mountains, and there is much evidence of former quarrying activities. The harbour wall now shelters a small sandy beach about 100 yards wide, with two (free) parking areas overlooking the beach. A concrete pier which extends beyond the wall has been declared unsafe and looks ready to collapse, but is still used by anglers. The immediate shore in both directions from here is rocky and backed by banks of boulder clay. The Yr Eifl mountains (translates as 'the forks') overlook the beach and provide a dramatic backdrop. Facilities include (seasonal) toilets, cycle stands, picnic tables and a slipway onto the sand. Swimming is generally safe within the harbour area. It's also one of the Llyn peninsula's surfing beaches, but not really suitable for beginners. Dogs are allowed at all times.
On the coastal path just to the south is the National Trust's Morfa property, with an old iron ore adit near to the wooden gate. This has been blocked off after about 15 yards and also has about a foot of water on the floor, and is not worth exploring.