Despite the presence of famous nudist centres (in Cap d'Agde and Port Leucate), the Languedoc-Roussillon region is not the best beach destination to practice naturism.
In the Hérault department, there is a wide beach between Villeneuve lès Maguelone and Frontignan where you can practice naturism outside Cap d'Adge. At Sérignan, there is also a reserved area along with a naturist campsite (rare in the south of France).
In the Aude region, an area is specially reserved for nudists near Port-Leucate. Access is simple for non-residents. In Port-la-Nouvelle, one can practice naturism in the wildest area called Montilles. A beach in Fleury d'Aude is also authorized but access is more difficult (unless you are a resident of the neighbouring campsite).
In the Pyrenees Orientales department, several small resorts welcome nudism with reserved beaches like Torreilles, Elne and St Marie. On the beaches of Côte Vermeille, naturism is not allowed but there are discrete small creeks...