This article considers the international legal obligations relevant to States when withdrawing from situations of armed conflict. While a growing literature has focused on precisely when armed conflicts come to a legal end, as well as obligations triggered by the cessation of active hostilities, comparatively little attention has been paid to the legal implications of withdrawals from armed conflict and the contours of the obligations relevant to States in doing so. Following in the wake of just war scholarship endeavouring to distil jus ex bello principles, this article examines States’ obligations when ending their participation in armed conflicts from the perspective of international humanitarian law (IHL). It shows that while it is generally understood that IHL ceases to apply at the end of armed conflict, this is in reality a significant simplification; a number of obligations actually endure. Such rules act as exceptions to the general temporal scope of IHL and continue to govern withdrawing States, in effect straddling the in bello and post bellum phases of armed conflict. The article then develops three key end-of-participation obligations: obligations governing detention and transfer of persons, obligations imposed by Article 1 common to the four Geneva Conventions, and obligations relating to accountability and the consequences of conflict.