The safe third country concept is based on the assumption that an applicant for international protection could have obtained it in another country and therefore the receiving state is entitled to reject responsibility for the protection claim. The safe third country concept is applied as a ground for declaring an application inadmissible and barring applicants from a full examination of the merits of their claim, as is the case for the “first country of asylum” concept, which covers refugees who have already obtained and can again avail themselves of protection in a third country. Member States’ practice shows considerable disparities in the way safe third country rules have been applied, with some adding to the list of countries they consider safe recently as reaction to the 2015/16 arrivals, while at the same time other Member States are becoming more reluctant to apply the concept. In this context, the proposals included in the reform of the Common European Asylum system initiated in 2016 include a set of new provisions regarding safe third country concepts. Specifically, a key provision of the proposed Regulation on asylum procedures is to make the application of safe third country (and first country of asylum) criteria mandatory, instead of leaving it at the discretion of the Member States as it is the case under the current Procedures Directive. Moreover, the Commission proposes to progressively move towards full harmonization in this area, by replacing national safe country lists with EU lists or designations within five years of entry into force of the Regulation.