The following guide applies to all UK and EU citizens, including those from Ireland, Norway, Switzerland, and Croatia: you will need a valid passport and either an ESTA or a visa to enter the United States. Most visitors hiring an RV in Dallas can stay for up to 90 days under the Visa Waiver Program with an approved ESTA, which should be applied for at least 72 hours before departure. If you are not eligible for the VWP, you will require a B-1/B-2 visitor visa. On arrival, U.S. Customs and Border Protection may ask about your trip, so be prepared to show proof of onward travel, accommodation, and sufficient funds. For the most accurate rules, check the official U.S. government website before traveling.