The question of jurisdiction over illicit activities in the Mediterranean Sea is the focus of the present article. It is posited that enhancement of the ordre public and the rule of law in the Mediterranean requires the prior establishment of precise, foreseeable and accessible domestic laws, as well as of the requisite jurisdictional nexus between the forum State and the illicit activity. Accordingly, the issue of legislative and enforcement jurisdiction over such activities, such as the smuggling of migrants, drug trafficking and international terrorism will be canvassed. These activities and the threats they pose for the security and the public order of the States bordering the Mediterranean Sea loom large in the current discourse over enforcement action in the region. However, the centre of attention has mainly been enforcement as such, and not the need for prior establishment of enforcement jurisdiction.