This paper tackles the issue of the validity of Collective Action Clauses (CACs) from the international law perspective, particularly in light of the European Convention on Human Rights (ECHR) and the possibilities of litigation over CACs before the European Court of Human Rights. This analysis goes beyond a common intuition according to which the contractual nature of the relationship rules out any possibility of ECHR litigation, in particular assessing the potential liability of Eurozone member States that decide to trigger these CACs in the context of the Eurozone sovereign debt crisis. It contributes to determine whether or not the protection granted by the ECHR could be used by holdout creditors to distort the efforts carry out by debtor States to restructure its debt. Section 1 examines the scope of application of the ECHR, without finding any compelling argument against its potential engagement through the utilization of CACs, even in the case of trust structures used in some agreements. Section 2 then focuses on the potential engagement of the protection of possession (Article 1 Protocol 1 ECHR) by holdout creditors before the European Court of Human Rights. Specifically, in light of the ECHR case law, it is argued that a case could be made by holdout creditors for the engagement of the “peaceful enjoyment of possession”, embedded in Article 1.