To travel from the UK to Alaska in 2026, you primarily need a valid British Citizen passport and an approved ESTA (Electronic System for Travel Authorization). Since Alaska is a U.S. state, British citizens qualify for the Visa Waiver Program, but you must apply for the ESTA online at least 72 hours before your flight. In 2026, your passport must be a biometric "e-passport" and should ideally have at least six months of validity remaining beyond your planned date of departure from the U.S. If you are arriving in Alaska via a cruise from Canada (e.g., Vancouver), you may also need an Electronic Travel Authorization (eTA) for Canada, depending on your transit path. As of March 2026, there are no mandatory COVID-19 vaccination requirements for entry, but you should carry proof of standard travel insurance that covers high-cost medical care in the U.S. It is also a "pro" tip to carry a printed copy of your return flight itinerary and your first night's accommodation details, as U.S. Customs and Border Protection officers frequently request this information during the primary inspection at your first point of entry into the country.