A ship registration, often called a 'flagging', is the formal act of assigning a vessel to a national authority and granting it a unique identification number. It establishes the legal identity of the vessel, defines its flag state, and subjects it to that state’s laws, safety standards and taxation regimes. Registration is a prerequisite for international trade, crew licensing and port entry, making it a cornerstone of maritime law.
The registration process varies by jurisdiction but typically requires vessel construction data, ownership proof, and safety certificates such as the International Convention for the Safety of Life at Sea (SOLAS) compliance. Once accepted, the vessel receives a registration number and a flag‑state certificate, enabling it to operate legally on international waters. Failure to register or maintain proper documentation can result in fines, detention, or loss of crew eligibility, underscoring the critical nature of timely compliance.