This article aims to introduce an in-depth conversation between International Relations (IR) and criminology about security practices and security studies. Too often each discipline has ignored the possibility of a dialogue, or has just borrowed ideas from the other discipline, unreflexively. This has created even more difficulties. But, it is possible to decolonize the topic of security from these traditional approaches, by connecting critical approaches on both side as they share an episteme based on an understanding of the practices of (in)security and the experiences lived by human beings. This is particularly the case of the convergence between the PARIS school of liberty and security analysing (in)security practices and critical criminologists interested in ‘everyday practices of security’, once they realize on both side that the internal and external security dimensions they study, are neither two different phenomena, nor the very same one, fusional and globalized at the same moment, but a set of differentiated practices that are nevertheless connected along a Mobius strip.