The Most Healing Seawater Spas in Biarritz. A combination of French, Basque and Spanish lifestyles has created a vibrant hotbed of culture, evident in its mix of cuisine, architecture and local customs. It’s typically associated with wealth, partly due to its noble ties. Over the years the city went from operating prosperous whaling and sea-based industries, to harboring a growing tourism trade that gathered in popularity from the 18th century onwards. In France, Biarritz has long been held as a leading centre of thalassotherapy – also known as seawater treatment. It’s one thing in particular that this coastal city has in abundance, and health experts say November is the perfect time to indulge. Get massaged and soaked spa-style with a range of natural sea water and seaweed treatments, or just relax in warm sea water pools. Several of the top hotels offer spa therapies, or try the likes of Thermes Marins on Rue de Madrid for a more affordable option.