For citizens of the United States, travel to the U.S. Virgin Islands (USVI)—which includes St. Thomas, St. Croix, and St. John—is not considered international travel. Because the USVI is a U.S. territory, it is classified as domestic travel. U.S. citizens are not required to present a passport when arriving from the U.S. mainland, though they must carry a government-issued photo ID. However, there is a unique twist: the USVI is a "separate customs territory" from the mainland. This means that when you depart the islands to return to the U.S. mainland or Puerto Rico, you must pass through a U.S. Customs and Border Protection checkpoint. During this process, you will be asked about your citizenship and any goods you are bringing back. While a passport is not mandatory for U.S. citizens, it is highly recommended to carry one as it serves as the ultimate proof of citizenship and makes the customs process much smoother. For non-U.S. citizens, the same visa and passport requirements apply as if they were entering the mainland United States.