It is generally considered to run from the Llŷn Peninsula in the north to St. Davids Head in the south. The bay is comparatively shallow and contains many fine safe beaches which are the mainstay of family-friendly holiday resorts like Porthmadog, Pwllheli, Barmouth, Aberystwyth and Cardigan. It is an area of natural beauty, with dramatic cliffs and sandy beaches.
The area benefits from the warming effect of the Gulf Stream and dolphins are regularly sighted in the bay. During the summer of the "Great Drought" in 1976, water temperatures in the bay reached as high as 79°F (26°C).