If you are a British citizen, you do not need a passport to enter Ireland. However, some carriers and airlines might require identification. Irish immigration officers check the ID of all passengers arriving by air from the UK and might ask for proof of British nationality, particularly if you were born outside the UK.

As of February 25, 2026, travel requirements within the Common Travel Area (CTA) have seen significant shifts due to airline policy changes. While the UK Government does not legally require a passport for domestic travel between Great Britain and Northern Ireland, Aer Lingus and Ryanair now mandate a valid passport or Irish Passport Card for all flights between the UK and Ireland (including Belfast routes for some carriers to ensure network consistency). However, British Airways and several ferry operators continue to accept other forms of government-issued photo ID, such as a UK driving license, for travel between Great Britain and Belfast. For non-British or Irish citizens, the new UK ETA (Electronic Travel Authorisation) requirements that went into effect in 2025/2026 may apply if entering from the Republic of Ireland. Always check your specific carrier’s documentation rules at least 48 hours before departure to avoid being denied boarding despite the legal flexibility of the CTA.