This paper is a preliminary investigation of Irish identity and citizenship in the aftermath of the decision of the UK to leave the European Union. It identifies three significant impacts: the marked increase in applications for citizenship in the Republic of Ireland from residents of Northern Ireland and Britain and the justifying narratives for those applications; the respondent narratives in the Republic about what it means to be Irish; and the effects on ideas of Ireland as an all-island identity. We consider the ways in which access to Irish citizenship is bordered by narratives of ethnic belonging and draw attention to how Irish citizenship is ‘bordered’ in the newsmedia. Through an examination of newsmedia and social media representations of and explanations for the post-Brexit rise in applications, we explore the interrelationship between strategic and affective aspects of citizenship and national identity and the possibilities of a resurgence of Irish ethnic nationalism post-Brexit. Through this case study, we aim to signal critical sites of change and frameworks of analysis for ongoing study of the specific situation of the island of Ireland as well as the practice of citizenship in the shifting geopolitics of the early twenty-first century more broadly.