In 2026, the list of places UK citizens can visit without a passport is extremely limited due to post-Brexit travel regulations. The only sovereign country you can visit without a passport is the Republic of Ireland, thanks to the Common Travel Area (CTA) agreement; you only need a valid "official" photo ID like a driving license. Beyond Ireland, you can travel to Isle of Man, Jersey, and Guernsey (the Channel Islands) without a passport, as these are part of the British Crown Dependencies. For every other destination, including the entire European Union (France, Spain, etc.), a valid passport is now mandatory. Furthermore, for 2026 travelers, you must now also have an ETIAS (European Travel Information and Authorisation System) linked to that passport for entry into the EU. The "pro-tip" for 2026 is that while you don't "need" a passport for the CTA, some airlines (like Ryanair) have their own private policies requiring a passport for all international flights including Ireland, so always check your carrier's fine print.