For citizens and residents of the United States, traveling to Hawaii does not count as leaving the country. Hawaii became the 50th U.S. state in 1959, and as such, it is a domestic destination. You do not need a passport to fly from the U.S. mainland to Hawaii, although as of 2026, you must have a REAL ID-compliant driver's license or another federally accepted form of identification to pass through airport security. Your mobile phone plan will typically treat Hawaii as a domestic zone with no roaming charges, and the currency is the U.S. dollar. However, there is a unique "agricultural border" managed by the USDA. Upon departure from Hawaii, your luggage must pass through an agricultural inspection to ensure you are not transporting invasive species or certain fruits/plants to the mainland. While it feels like a tropical international getaway, you are legally and administratively remaining within the United States the entire time.