Piracy refers to robbery or criminal violence committed by an attacker on board or on board another ship or coastal area, usually aimed at stealing goods and other valuables or property. People who engage in piracy are called pirates. The earliest pirate record was in the 14th century BC, when a group of sea predators attacked the Aegean Sea and the ships of Mediterranean civilization. Narrow channels to transport goods to predictable routes have long created opportunities for piracy, private trading and commercial attacks. Historical examples include the waters of Gibraltar, the Malacca Strait, Madagascar, the Gulf of Aden and the English channel, whose geographical constraints have contributed to pirate attacks. Parallel lines on land refer to bandits and robbers ambushing passengers on highways and mountain passes. In private, the method similar to piracy is used, but the captain acts under the order of the state, authorizing the capture of the merchant ships belonging to the enemy country, which makes it a legitimate form of war like activities of non-state actors.

Although the term may include acts committed in the air, on land (especially across borders or in connection with taking over and robbing cars or trains), or in other major waters or on the coast, this article focuses on piracy at sea. It usually does not include crimes against people travelling on the same ship as the perpetrator (for example, a passenger stealing from someone else on the same ship). Piracy or piracy is the name of a specific crime in customary international law, as well as the name of several crimes in many state and municipal laws. At the beginning of the 21st century, maritime piracy against transport vessels remained a major problem (estimated at $16 billion a year globally in 2007), especially between the Red Sea and the Indian Ocean, off the coast of Somalia and the Straits of Malacca and Singapore.

Today, pirates with automatic weapons and rocket propelled grenades use small motor boats to attack and board ships, a strategy that takes advantage of the few crew members on modern cargo and transport ships. They also use larger vessels (called "mother ships") to supply smaller motor boats. The international community faces many challenges in bringing modern pirates to justice, as these attacks often take place in international waters. Moreover, many countries have used their naval forces to protect private ships from pirate attacks and to hunt down pirates. Similarly, some private vessels are taking steps to protect their vessels and crew from piracy, such as the use of armed guards, high-pressure hoses or sound cannon to fire back passengers, or the use of radar to avoid potential threats.