Llansteffan (originally Llanstephan) lies 7 miles south of Carmarthen on the west side of the Towy estuary. The beach is mostly sand and cockle shells backed by an area of rough grass, behind which are the (free) car parking areas. An asphalt path with plenty of benches and picnic tables runs along the back of the beach. The sandy beach continues northwards for about a mile up the estuary. To the south the sand continues to Scott's Bay, backed by low cliffs of sandstone and siltstone. Signs warn against attempting to cross the estuary and swimming, although swimming is generally safe at high tide before the tide turns. Dog restrictions apply from 1st May to 30th September. The restricted area runs from the lane which runs down to the shore (100 yards south of the car park) to a point roughly 100 yards before the northern car park.
Facilities here include toilets, a small play area, fish and chip and ice cream vendors, a tea room / beach shop, cycle parking, a telephone and a slipway onto the sand. Llansteffan village is a short walk away and has two pubs and a village store.
Overlooking the beach and village is the imposing Norman castle. Officially the opening times are 10.00 - 16.00 but as there's no gate of any kind, access is possible at any time. There are good views from the one accessible tower.