Maritime terrorism is the maritime dimension of contemporary asymmetric warfare conducted by international terrorist organizations. Maritime terrorism is the undertaking of terrorist acts and activities within the maritime environment against vessels or fixed platforms at sea or in port, or against any one of their passengers or personnel, against coastal facilities or settlements, including tourist resorts, port areas and port towns or cities as well as any maritime activity intended to support the existence or the purposes of one or more terrorist organizations through licit or illicit means sea-born migration flows when exploited for the movements of terrorists, of terrorism backers/supporters and for financial profit when it involves people trafficking and migrants smuggling perpetrated by transnational organized crime depending on a terrorist organization. Criminal trafficking's are directly relevant activities for terrorist organizations for perpetrating their purposes. Maritime dimension offers an ideal environment to be exploited by criminal and terrorist organizations. Maritime environment and industry have intrinsic hinders to properly counter illicit phenomena and facilitating legal commercial and migration flows meanwhile which are vital for contemporary and future interdependent economy. Piracy and armed robbery against vessels are a plague to maritime security and global shipping. Such phenomena have implications for maritime shipping and are a meaningful damage for international trade and maritime traffic. Piracy has a functional role for terrorist organizations when it pursues aims of terrorism funding. According to many analysts, some terrorist groups are directly linked with piratical aggressions. Terrorist groups demonstrated to be trained to exploiting maritime environment for attacking offshore and ashore civilian and commercial targets as well as military vessels and to acquire sensitive information. Key factors enabling maritime terrorism are open registers and flags of convenience. National Maritime shipping industries would require stricter rules and implementation of policies not offering the possibility to easily conceal the real identity of ship owners and maritime companies' businessmen. Corruption and lack of accountability characterize flags of convenience offering good opportunities for criminals money launderers, or the insane practice of sinking a ship for profiting over insurance damages. Flags of convenience are the maritime sphere of offshore financial centers and bank secrecy. Phantom ships are assets of terrorist organizations and they compose certain fleet operating across the world. Maritime terrorism poses serious concerns to the international supply chain security as it affects worldwide international commercial shipping. When estimating harbors risks and exposition to terrorist attacks, if they serve as hubs for terrorist purposes such function could be a deterrent for this type of incidents. Activities aimed at countering maritime terrorism are a significant contribution to reduce international instability since the high exploitation of the sea for terrorist and criminal purposes is a concerning aspect of contemporary global (dis)order.