St. Martin -- an island in the Caribbean about 190 miles east of Puerto Rico -- comprises two parts: the French-owned Saint-Martin and the Dutch-owned Sint Maarten. When planning a trip to the island, all non-citizens must present a valid passport from their country of residence; some travelers will also need to present a visa. Visitors will encounter slightly different requirements for entry to each half of the island.
About St. Martin
St. Martin draws tourists to its sandy shores for its bounty of beaches, casinos, restaurants and nightclubs. The Dutch side hosts the majority of the island's nightlife, while the French side has the island's international airport, Princess Juliana International Airport. Tourists also hop off cruise ships to explore St. Martin and take advantage of its duty-free shopping; no border guards or customs are between the two halves of the island.
The French Side
The northern part of St. Martin is owned by France, and it is considered part of the French West Indies. For citizens of France or any other European Union country, you must simply present a national I.D. card or a valid passport. All other travelers will need to present a valid passport as well as a return or transfer ticket; unless your stay will extend longer than three months, you don't need to obtain a visa.
The Dutch Side
The southern half of the island, Sint Maarten, is owned by the Netherlands. To visit this part of the island, United States citizens must present a valid passport as well as a continuing/return ticket showing their intent to leave the island. Because the Netherlands is part of the Schengen Agreement, U.S. citizens can enter Sint Maarten for up to 90 days as a tourist or for business purposes without obtaining a visa. Another requirement is that your passport must be valid for at least three months after you plan to exit Sint Maarten.
If you don't have a valid passport and plan to visit the island, you'll want to begin the renewal process or regular application process as soon as possible, as it can take up to six weeks to process your application and get your new passport. If you plan to visit the island for more than 90 days, or you are visiting as a student, you must obtain a visa and go through additional steps.