It is a US territory but since it's a port of entry you have to do customs. You will go through Customs and Immigration upon your return to the mainland from the USVI, not upon your arrival to the USVI from the mainland. You will also go through immigration if you make a trip to the BVI. Hope that helps!

Yes, you must go through U.S. Customs and Border Protection (CBP) screening when traveling from the U.S. Virgin Islands (St. Thomas, St. Croix, or St. John) back to the U.S. mainland or Puerto Rico. Even though the USVI is a U.S. territory, it is maintained as a "separate customs territory" to protect the mainland from invasive species and to regulate high-value duty-free imports. In 2026, you will undergo this inspection at the airport in the USVI before you board your flight, meaning you arrive at your mainland destination as a domestic passenger. You must declare all purchases, including the generous $1,600 duty-free allowance per person (double the typical international limit). While a passport is not technically required for U.S. citizens—a REAL ID-compliant driver's license and a birth certificate suffice—CBP strongly recommends a passport as it is the most efficient document for the 2026 biometric scanners. You should also be prepared for an agricultural inspection to ensure no prohibited fruits, vegetables, or plants are being brought to the mainland.