Les Sables-d'Olonne is a seaside resort and port on the Atlantic coast of western France. A subprefecture of the department of Vendée, Pays de la Loire, it has the administrative level of commune. On 1 January 2019, the municipalities of Olonne-sur-Mer, Château-d'Olonne and Les Sables-d'Olonne merged, retaining the latter name.