Patient and public involvement (PPI) in healthcare aims to give people a voice in decisions about issues that affect them. This document discusses PPI related to rare diseases on both sides of the Ireland border. It outlines the development of rare disease networks and plans in both the Republic of Ireland and Northern Ireland. Cross-border collaboration through conferences and information sharing has raised awareness of rare diseases and identified areas for increased cooperation, such as research, transplant services, genetics services, and clinical trials. Moving forward, focus remains on implementing plans, continuing public involvement, addressing potential Brexit impacts, and securing funding.