Take affordable sailing lessons (€38 an hour) at the St. Barth Yacht Club (590-27-70-41); they also rent out their new fleet of fourteen-foot Lasers at the same rates. If the purse strings are a little looser, opt for renting a sailboat or catamaran—Cote Mer has a 47-foot catamaran, Nuage III, for €720 for a half-day rental, while Yannis Marine has an impressive collection of sport yachts, including the 31’ Contender for deep sea fishing trips. It runs €750 for a half-day rental.
Find plenty of room to sprawl out on St. Barts' 37 pristine beaches in the off-season, when temperatures hover around 78 degrees. Bask in isolation at the idyllic Gouverneur Beach in the south, which also has excellent snorkeling (most hotels provide gear), or on the long stretch of sand at Flamands. Its choppy waters are good for wave-jumping and wind-surfing. If you feel social, lunch at the sceney restaurants along Baie de St. Jean—restaurants La Plage at the Tom Beach Hotel and Nikki Beach also offer beach-chair rentals.
Skip the shore for a day and head to Gustavia for some retail therapy. Summer sales are the best time to get your fill of Cavalli, Cartier, Dior, and Vuitton, all marked down by as much as 70 percent during semi-annual sales. Check out some of the lesser-known stores, such as Cachemire Crème (Rue du Bord du Mer; 590-52-48-42), which carries buttery soft cashmere for all ages. Locally made Ligne St. Barth luxe skin-care products are always a good buy. Stock up at the flagship store in Lorient (Route de Saline; 590-27-82-63). Go early—or late, as many shops close between noon and 4 p.m.