U.S. Virgin Islands John, St. Croix and St. Thomas. Since they're U.S. territories, a government-issued photo ID or birth certificate with a raised seal will suffice.

For U.S. citizens, the U.S. Virgin Islands (USVI)—consisting of St. Thomas, St. Croix, and St. John—are the only parts of the Virgin Islands you can visit without a passport. Because the USVI is an unincorporated territory of the United States, travel from the mainland or Puerto Rico is considered a "domestic" flight. You only need a government-issued photo ID (like a Real ID-compliant driver's license) and a raised-seal birth certificate to re-enter the mainland. However, it is very important not to confuse them with the British Virgin Islands (BVI), which include Tortola, Virgin Gorda, and Jost Van Dyke; those require a valid passport for entry. Even though you don't need a passport for the USVI, it is still the recommended form of ID because it simplifies the customs and border protection process when you depart the islands for the U.S. mainland. If you plan to take a ferry over to the British side for a day trip, you will absolutely be denied boarding without a passport.