Abstract
This article examines the international legal grounds and limits for the exercise of state jurisdiction over stateless vessels on the high seas. The topic has gained practical importance due to the increasing use of vessels lacking or unable to prove nationality in contexts such as irregular migration, smuggling, trafficking in persons, IUU fishing, and other forms of transnational maritime crime. At the same time, legal uncertainty persists regarding the permissible scope of maritime enforcement measures against such vessels. The purpose of the article is to clarify when states may lawfully conduct visit, inspection, detention, and seizure in relation to stateless vessels and to identify the minimum safeguards required to ensure compliance with international human rights obligations and, in migration-related operations, the principle of non-refoulement. The study employs doctrinal legal analysis and treaty interpretation of the law of the sea, comparative assessment of competing scholarly approaches to the status of stateless vessels, and an analysis of relevant judicial and operational practice. The findings propose practical criteria for establishing statelessness, distinguish between prescriptive and enforcement jurisdiction, and articulate necessity, proportionality, and procedural good faith as baseline requirements for lawful intervention on the high seas.