Traveling from Great Britain to Belfast by ferry in 2026 still falls under the Common Travel Area (CTA) rules, which technically allow for travel without a passport for British and Irish citizens. However, most major ferry operators (like Stena Line and P&O) and airlines have tightened their requirements for "operational certainty." You will need a valid form of photographic ID; while a passport is the "gold standard" and most recommended, a valid UK or Irish driving license is generally accepted for ferry travel. Note that as of February 25, 2026, some carriers like Aer Lingus have made passports mandatory for flights, but ferries remain a primary alternative for those traveling with alternative photo ID, provided it is current and matches the name on the booking.