Duhaime's Law Dictionary

Tidal Waters Definition:

Bodies of water within a state's territorial waters and that are subject to the ebb and flow of ordinary tides, whether navigable or not, and usually excluding harbors or lakes.

Related Terms: High Seas, Continental Shelf, Territorial Sea

A term of international law and of maritime law by which a coastal state will distinguish that part of the water adjacent to the coast which extends between the high and low tide mark, and for a variety of purposes such as, but  not limited to, jurisdiction, property rights, environmental regulation, fishing, transportation or construction.

Some states, such as England, further distinguish tidal waters by referring to the high and low tides in Spring.

§255 of the Merchant Shipping Act 1995 states:

"Tidal water means any part of the sea and any part of a river within the ebb and flow of the tide at ordinary spring tides, and not being a harbour."

Other jurisdictions prefer the term tide water.

Bouvier, in his 1897  American law dictionary, wrote:

"Tide-water is not limited to water which is salt, but embraces, also, so much of the water of fresh rivers as is propelled backwards  by the ingress and pressure of the tide."


  • Merchant Shipping Act 1995, UK Public Acts 1995, Chapter 21

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