The regime of maritime security includes security of navigation and security in port. It is one of the essential objectives of maritime policy, which also covers military aspects. Security issues cover such criminal aspects as piracy, armed robbery against ships, terrorism, and other unlawful acts at sea. The common concept of maritime security fails in national and international legislation. However, these types of the mentioned crimes are prosecuted under national and international law. The maritime security regime is based on the assessment and protection of the vulnerable places in the maritime transport chain as well as the prosecution of criminals. The security measures are expensive, but if one considers the potential costs of a single terrorist act in an intensive sea lane on, for example, an oil tanker, it may overwhelm the implementation costs.