In 2026, UK citizens must navigate the full implementation of the ETIAS (European Travel Information and Authorisation System). To enter Spain, you primarily need a valid British Passport that was issued less than 10 years before the date you enter the country and is valid for at least 3 months after the day you plan to leave. Additionally, you must have your approved ETIAS authorization linked digitally to your passport, which costs approximately €7 and is valid for three years. Since the UK is now a "third country" under Schengen rules, Spanish border guards may also ask for "Proof of Resources" (showing you have enough money for your stay), proof of accommodation (such as a hotel booking), and a return or onward ticket. While a visa is not required for stays under 90 days within a 180-day period, UK travelers should also carry a GHIC (Global Health Insurance Card) or a valid EHIC to ensure access to state healthcare, as travel insurance is highly recommended but not a strictly "mandatory" entry document.