For U.S. citizens, St. Croix (part of the U.S. Virgin Islands) is considered a domestic destination, meaning you do not need a passport to enter when traveling directly from the U.S. mainland or Puerto Rico. Because it is a U.S. territory, it is essentially like flying between states. However, as of May 7, 2025, travelers must have a REAL ID-compliant driver's license or another acceptable form of ID (like a passport or Global Entry card) to clear TSA security at the airport. It is also important to note that while you don't need a passport to arrive, the USVI is a "port of entry," so you will technically pass through a pre-flight Customs and Border Protection (CBP) check when returning to the U.S. mainland. Carrying a passport—even if not strictly required—often makes this process faster. Additionally, if you plan to take a boat trip to the nearby British Virgin Islands (BVI), a passport is mandatory. Non-U.S. citizens must follow standard U.S. visa and passport entry requirements.