The temporary presence exception provides vessels engaged in international transport with a defense to patent infringement when traveling outside of the vessel’s home nation. The exception was adopted internationally and added to the Paris Convention in an effort to (1) minimize the costs associated with transporting between various countries with distinct national patent systems and (2) eliminate international tensions arising from charges of patent infringement when in foreign lands. Although the modern enactments of the temporary presence exception further these goals, this article argues that the exception is overbroad. Specifically, this article argues that the exception’s reciprocity requirement, in concert with the rise of modern international transportation registries and lease arrangements, creates a loophole in which owners can completely eliminate worldwide patent infringement liability for their vessels. This article provides a model registry system and judicial interpretation that are designed to close this patent infringement loophole while maintaining the original goals of the exception’s enactment.