Crime aboard Ships: Criminal Jurisdiction and the Problem of Enforcement beyond Territorial Waters

Abstract

Crimes committed aboard ships outside territorial waters expose a recurring weakness in maritime criminal law. The problem is often framed as uncertainty over which state has jurisdiction, although the harder question appears after a jurisdictional basis has been identified. A flag state may be entitled to prosecute, another state may rely on the nationality of the offender or victim, and a port state may later gain physical access to the vessel. None of those connections guarantees arrest, evidence preservation, witness availability, or prosecution. This article examines the separation between jurisdictional entitlement and enforcement capacity through doctrinal analysis of UNCLOS, relevant maritime-security instruments, international decisions, and. Article 92 is read primarily as a rule against unauthorized enforcement on the high seas rather than a complete bar to concurrent prescriptive or adjudicative claims. The overlap can be legally manageable, while enforcement remains fragmented by ship mobility, weak flag-state control, dispersed evidence, and dependence on later port access. A sequenced model of cooperation is proposed that preserves flag-state primacy while enabling early evidence preservation, notification, port-state assistance, and coordinated prosecution decisions.