If you hold a Free Travel Pass issued by the Republic of Ireland’s Department of Social Protection, you can use it to travel to Belfast, but there are specific rules for the cross-border journey. Under the "All-Ireland Free Travel Scheme," seniors (66+) with a valid Public Services Card can travel for free on the Enterprise train service and various bus routes between the Republic and Northern Ireland. However, while the journey to and from Belfast is covered, your pass generally does not grant you free travel on "local" Translink services within Belfast city (such as the Glider or local Metro buses) unless you are also a resident of Northern Ireland with a specific Senior SmartPass. It is always best to check in with the ticket office at Dublin Connolly or your local Bus Éireann station before boarding to ensure your specific pass is validated for the trip. For those under 66 with a disability-based travel pass, the rules for cross-border travel can be more restrictive, so verifying your eligibility on the Citizens Information website is a necessary step before planning your trip.