Three Rivers Estuary is the confluence of the rivers Tywi, Taf and Gwendraeth. It lies in Carmarthen Bay.

Withim the bay there’s lots of very beautiful spots – Caldey Island near Tenby. Towns and villages in the bay include, from east to west: Llanelli, Burry Port(Porth Tywyn), Pembrey(Penbre), Kidwelly(Cydweli), Ferryside(Glanyfferi), Llansteffan, Laugharne(Talacharn), Pendine(Pentywyn), Amroth, Wisemans Bridge(Pont-yr-ŵrddoeth), Saundersfoot and Tenby(Dinbych y Pysgod).

There are fine beaches at Pendine Sands, Cefn Sidan, Laugharne, Llansteffan and Ferryside.

The cockle and mussel beds are located in these areas.

— excerpt from Carmarthen Bay Wikipedia page