Border control and the Common Travel Area. There are no routine passport controls in operation for Irish and UK citizens travelling between the 2 countries. However, you must show identification to board a ferry or an airplane, and some airlines and sea carriers only accept a passport as valid identification.

While the Common Travel Area (CTA) agreement technically allows British and Irish citizens to travel between the UK and Ireland without a passport, the reality in 2026 is that you almost always need a passport due to airline policies. Major carriers like Ryanair and Aer Lingus have now made it a strict requirement for all passengers to present a valid passport or an Irish Passport Card to board flights between the two countries. They no longer accept driver's licenses or other forms of photo ID for these routes. If you are traveling by ferry (such as Stena Line or Irish Ferries), you may still be able to use a valid driver's license with a photo, as they are often more lenient under the CTA rules. However, even on a ferry, you may be asked to prove your nationality to border officials, for which a passport is the only definitive document. For non-British/Irish citizens, a passport is mandatory for all travel between the UK and Ireland, and depending on your nationality, you may also require a visa for one or both jurisdictions.