ABSTRACT This article reexplores Ireland’s final exit from the Commonwealth in 1948–49, deploying Brexit as a comparative heuristic and organising device. The existing literature has stressed both Ireland’s symbolic motives in fully breaking with the Crown and how it retained many the advantages of Commonwealth membership whilst avoiding its obligations. It is true that, at least from the later 1930s, Ireland was more akin to an associate as opposed to a full Commonwealth member and that both significant support for the Irish position from Commonwealth members with large Irish diaspora populations and decentralisation in the Commonwealth itself made for a relatively hospitable negotiating environment. Nevertheless, the Brexit comparison helps highlights the considerable trade and citizenship links, including with the UK, which were linked to Commonwealth association and which secession thereby put at risk. It similarly highlights the price Ireland paid for its exit including a public commitment to make reciprocal citizenship rights generally available to all Commonwealth members, a strengthening of Northern Ireland’s links with Great Britain and a loss of participation rights in key Commonwealth preference, Sterling Area and related fora. The ultimately rather limited significance of that price may relate more to a subsequent fundamental refocusing of both Irish and UK geographic priorities towards Europe in subsequent decades.