The impact of immigration on national labour markets is of increasing concern for policy makers. Employment, unemployment and wages are the traditional channels examined by social scientists when bringing evidence to the decision-making table. However, this paper contributes to the more limited empirical literature on migration's effects on unemployment duration, by exploiting the deregulation of migration policies between Switzerland and the European Union. It applies a counterfactual approach and implements difference-in-differences methodology paired with inverse probability weighting. This paper concludes ultimately that the abolition of the priority granted to local workers results in a rise in unemployment duration.