St Martin: sailing on Americas cup boats or, on the French side, a croissant and café au lait.
Greneda: in town, buy nutmeg, cloves and cinnamon, walk around the harbour. Eat nutmeg ice cream. Visit the stunning Grand Anse beach.
St Lucia: completely depends where your ship docks.
Barbados: Many many options !
Bon voyage about 8 years ago
Unless you are overnighting in Barbados you will probably only be able to shop, sightsee or go to the beach. Go to Accra beach for a good mix of locals and tourists, go to Bathsheba for exciting Atlantic vistas or go duty free shopping on Broad Street about 8 years ago