St. Maarten. Since 2010, Sint Maarten has been a constituent country within the kingdom of The Netherlands. It comprises the “Dutch side” of the island of Saint-Martin, the other half being a French overseas territory. Philipsburg is its capital and a busy deep-water port city. It is a popular port for cruise ships, and consequently boasts a thriving duty-free shopping community, a range of resorts and villas, numerous leisure and sightseeing activities, as well as a well-served airport.