Definition
Operating or traveling along the coast between domestic ports, as distinguished from foreign or oceanic trade. In maritime and shipping law, a vessel is said to ply coastwise when it engages in commerce between ports within the same country — that is, domestic trade — rather than crossing to foreign ports. The term describes both the trade itself and the vessels engaged in it.
Common Language
Modern common usage (Wiktionary): Along the coast.
Historical common usage: Not independently defined in Webster's 1913 as a legal term; used in general navigation contexts to mean movement along or near a coastline.
Editorial note: The ordinary meaning suggests mere geographic proximity to the coast — traveling near shore. The legal meaning is more precise and more consequential: it describes a category of domestic commerce defined by the ports of origin and destination, not the vessel's physical route. A vessel running between Boston and Savannah is coastwise regardless of how far offshore it travels.
Core Elements
Coastwise trade turns on two defining characteristics:
1. Domestic ports on both ends. Both the port of departure and the port of arrival must be within the same country. Travel between a U.S. port and any foreign port, however geographically close, is foreign trade, not coastwise.
2. Domestic commercial purpose. The vessel must be engaged in trade or commerce — carrying passengers, cargo, or goods — between those domestic ports. The term is functional, not merely geographic.
Why It Matters in Research
The term carries significant regulatory weight in American law, most prominently through federal cabotage restrictions — laws reserving domestic waterborne commerce to U.S.-built, U.S.-flagged, and U.S.-crewed vessels. Researchers working with historical shipping records, customs documents, or vessel registration materials will encounter "coastwise" as a legal classification that triggers a distinct regulatory regime from foreign trade.
Two traps deserve attention. First, the coastwise/foreign trade distinction is not about distance or geography — it is about the nationality of the ports. A voyage from Miami to Havana (foreign) may be physically shorter than a voyage from Miami to Boston (coastwise), but they fall under entirely different legal frameworks. Historical sources sometimes use "coastwise" loosely to mean near-shore navigation, which can mislead researchers tracing regulatory compliance or licensing disputes.
Second, the definition has remained relatively stable in its core (domestic port to domestic port), but the statutory consequences attached to it have shifted over time. Pre-twentieth century materials may describe coastwise trade in contexts where modern cabotage statutes — most prominently the Jones Act — now impose stricter requirements. Researchers should not assume that a historical source's description of coastwise vessels reflects the same regulatory burden as modern usage.
Researchers working on inland waters should also note that rivers, lakes, and intercoastal waterways have at various times been included or excluded from coastwise trade definitions depending on the statute or regulatory context at issue. The corpus will surface this variation across different periods and subject areas.
Historical Dictionary Support
Black's Law Dictionary defines coastwise vessels as those "plying between port and port in the United States," explicitly contrasted with foreign trade vessels operating between a U.S. port and a foreign port. The entry cites a California decision (10 Cal. 504) to anchor this definition, though the practical significance of the term lies in federal law, not state courts.
What historical dictionaries do not address is the regulatory architecture built on top of this definitional foundation. Black's gives a clean functional definition but offers no guidance on how coastwise classification interacted with licensing regimes, customs requirements, or the evolving body of federal navigation law. Researchers relying solely on dictionary definitions will miss the legal machinery the term activates.
Jurisdictional Note
Coastwise trade is primarily a matter of federal law in the United States. The classification triggers federal statutes governing vessel registration, crew nationality, and cargo carriage rights. State law plays a minimal role in defining or regulating coastwise commerce, though state port regulations may apply independently.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia — Cabotage; Navigation and Shipping Law; Jones Act (Merchant Marine Act of 1920)