This article empirically analyses the political and legal construction of irregular migration across selected member states of the European Union. First, it considers how policies lay the preconditions for irregular migration. Second, it explores the role of politics and law in generating irregular migration. Thus, it carves out diverse and divergent practices across the EU and argues that these are related to divergent legal and political cultures among the member states. This reveals that regulations that are meant to prevent unwanted migration often have unintended side-effects and instead encourage irregular migration which is conceptualised as a policy gap and policy failure. The conclusion drawn from this is that some irregular migration can be avoided and that there is scope for accordingly reforming national laws.