Narbonne plage.

 Narbonne Plage is an easy 1 hour drive from Carcassonne along the autoroute.

The first and really important point is that the beach is not actually at Narbonne. When we first visited we had expected a drive through the City, through busy streets and then having a tricky time finding anywhere to park. The reality is that you reach Narbonne Plage from the autoroute by driving through vinyards and open countryside of domaine de clape. The ground is bone dry here and the road sweeps down from the hills, past a military radar dome and towards the beach.

There is a wide promenade and we never had any trouble parking. The beach is covered with fine beautiful sand but when the wind off the sea is strong the grains can sting!

When you stay in Carcassonne the local swimming places tend to be

Lac de Cavayere ( which can often be closed due to green algal blooms but still has a lovely grassy beach area, walks and boats).

Pradelle up in the Montagne Noire. A couple of degrees cooler than on the plains.Good swimming, boats and an ice cream kiosk.

Lac de Montbel. Lovely drive into the Ariege. However the sticky clay and lack of easy access can make it a little tricky when the water levels are very low.

Narbonne plage is the closest coastal beach and really not a long drive at all.

 This picture shows the beach looking up towards the promenade

and this shows the beach on a busy holiday, its very popular with the locals

 This picture shows the boats at Narbonne. Image credit. 

and a few videos

and here is the Google map for Narbonne plage