The analysis deals with the operation of Treaties and EU laws in determining international jurisdiction in the fields of both Public International Law, including human rights, and Private International Law regarding the implementation of ‘protective measures', towards the international protection of migrant children and adults. The relevance of different interrelated fields and Treaties within international law towards the determination of State competence and responsibility dealing with boat migration movements towards the protection of migrants may leave complex grey areas potentially jeopardising the certainty and predictability of law. The analysis does not aim to solve general issues of jurisdiction after the arrival of migrants in the territory of a State where an asylum request has already been filed, but it refers to the ‘overlapping' of international rules of competence and responsibility to determine State ‘protective' jurisdiction in order to identify which State, or States, should initially deal with asylum requests. In this article, it is advocated for better clarity in the implementation of the – interdependent – mechanisms provided by different Treaties dealing with the determination of international jurisdiction inherent to the international protection of ‘boat migrants'. Therefore, the analysis will focus specifically on the international rules of competence and responsibility applicable to the specific issue of boat migration, where particular attention is given to asylum seekers given their underprivileged vulnerable protection.