Maritime terrorism is as old as its history. From ancient times to the first decade of the 21st century, perpetrators of all kinds of violence, including kidnapping, sabotage and direct attacks on targets, have inhabited the high seas as well as the wider marine environment. Terrorism at sea becomes important when a significant part of the world's trade is carried out by sea. One of the challenges of dealing with terrorism at sea and the inefficiency of the means to deal with it is found in the Convention on the LAW of the Sea. Therefore, security in the seas is also considered a part of this convention; But in it, the issue of maritime terrorism is not addressed separately. Therefore, terrorist CRIMES in the seas and the fight against them are among the issues raised in international LAW, especially the international LAW of the seas, so that the first measures in this direction also go back to the era of the League of Nations. However, this article tries to use the descriptive and analytical research method while measuring the mechanisms of dealing with CRIMES in the sea territory, and examines the way of dealing with and suppressing terrorist CRIMES. Of course, according to the concern of coastal communities and international organizations caused by maritime terrorism, a suitable solution can be proposed, which is the participation of private companies to help fight terrorism in the sea, despite the disagreement about this approach and legal basis. It acted in international LAW.