The Belfast or Good Friday Agreement of 1998 makes provision for Northern Ireland to leave the United Kingdom and join a united Ireland through a unification referendum, if voters so wish. Yet, the provision is short on detail and has not been substantively explored. A Working Group on Unification Referendums on the Island of Ireland has recently sought to address this gap. In this article, the Working Group's chair and research assistant outline the project's methodology and key findings, covering overall referendum configurations and specific design features, as well as what steps might be taken in the coming years. The article also highlights two comparative lessons, relating to tensions between the values of informed consent and inclusive design, and between majoritarian and consensual politics. These tensions afflict many referendums, particularly on sovereignty questions. They cannot be resolved, but only tempered, through careful and inclusive design of referendum processes.