If one commits any crime at sea, they are considered a pirate.

Only acts of violence, detention, plundering, or destruction against other ships, aircraft, or people aboard them on high seas are considered piracy.

Only acts of violence, detention, plundering, or destruction against other ships, aircraft, or people aboard them on high seas are considered piracy.Nearly two-thirds of the world's surface is ocean waters. These areas are beyond any country's territorial waters and are not subject to respective criminal jurisdictions. Acts of piracy endanger the seafarers' welfare and security, threatening maritime security.

The United Nations Convention for the Law of the Sea (UNCLOS) is one of the major governing bodies over international maritime law. According to UNCLOS, piracy consists of any illegal acts of violence or detention, or any act of depredation, committed for private ends by the crew or the passengers of a private ship or a private aircraft directed on the high seas. Piracy occurs against another ship or aircraft, persons, or property on board such ship or aircraft, in a place outside the jurisdiction of any state (country). Only committing crimes at high seas as defined above makes one a pirate, not just any crime. Any act of voluntary participation in operating a ship or aircraft knowing it is a pirate ship or aircraft is also considered piracy.

Domestic laws play an essential role in establishing a legislative framework that allows for effective and efficient prosecutions of pirates. A state remains entitled to exercise any criminal jurisdiction established according to its domestic laws. UNCLOS noted in resolution 1918 (2010) that several states' domestic laws lack provisions criminalizing piracy or are deficient in criminal procedural rules needed to prosecute pirates effectively.

The Anti-Maritime Piracy Bill, 2019, for India has been drafted in accordance with UNCLOS, 1982. It applies to the sea beyond the Exclusive Economic Zone (EEZ), beyond 200 nautical miles from India's coastline. Currently, India does not have domestic legislation on maritime piracy. In the past, the Indian Penal Code (IPC) provisions about armed robbery and admiralty jurisdiction of certain courts have been invoked to prosecute pirates. However, India's sovereignty extends only up to India's territorial waters (12 nautical miles from the coastline).

It is to be noted almost all maritime laws refer to piracy when it occurs in international water and not domestic waters (out of a country's jurisdiction).