YES, Saint-Barthélemy (St Barths) is a French overseas collectivity (COM), Caribbean — so in the Europe zone for your French carrier. The Alosea St Barths eSIM is interesting for luxury vacations (one of the most upscale Caribbean destinations, frequented by celebrities at Christmas/New Year, iconic Bonne Année festive at Gustavia port) or to avoid plan restrictions. You connect to Orange Caraïbes, Dauphin Telecom or Digicel upon landing at Gustavia (SBH — pilots specially trained for this very short runway).