Law of the Sea and the Coastal State 

The United Nations Convention on the Law of the Sea (UNCLOS) provides a framework for the use of the oceans. It is this convention which specifies the territorial limits of a country and which defines whether a vessel is under the laws of its flag state or those of the state whose waters it is lying in.

Vessels are free to navigate the High Seas within the laws of their flag state and only a warship of their own nation has the right to intercept them (other than to confirm the nationality of the vessel) unless they are committing an international crime such as piracy.

Under UNCLOS vessels have a right of passage through the territorial waters of another country; all vessels exercising this right of passage must undertake a continuous and expeditious passage through territorial waters and may not engage in any activity which does not have direct bearing on the passage. They must also abide by international conventions - such as Safety of Life at Sea (SOLAS), the International Regulations for Preventing Collisions at Sea (COLREGS) - and the Coastal State has the jurisdiction to ensure that they do so.

The Coastal State may also have laws and regulations which such vessels must adhere to, to ensure safe navigation, regulation of maritime traffic, protection of navigational aids, facilities, pipelines, and cables, conservation and preservation of the environment and the living resources of the sea (including fisheries laws) and to prevent against infringement of customs, fiscal, immigration or sanitary laws and regulations of the coastal state.

The majority of cruising yachts will not however be regarded as being on a continuous and expeditious passage as they may be cruising along the coast, perhaps anchoring for lunch and they may also visit several ports within the Coastal State. These activities bring pleasure boaters under the jurisdiction of the Coastal State and they could then be required to adhere to all of their regulations.
 
UNCLOS also defines a country’s Internal Waters (waters which are landward of the Base Line) which includes many ports, harbours estuaries and bays and of course the inland waters such as rivers and canals.

If a vessel makes a continuous and expeditious passage through territorial waters to a destination within Internal Waters such as a port, the right of passage ends on entering Internal Waters. By voluntarily entering a port or the internal waters of another country a vessel submits to the jurisdiction of that country i.e. the Coastal or Port State, as Internal Waters are considered to be an integral part of a country. The authority of a state over foreign vessels in its internal waters is the same as those for a foreigner on its soil, which of course includes boat crews going out for dinner, sight seeing, shopping and generally making use of facilities ashore in their destination port.

The Coastal State however will generally refrain from interfering with the internal affairs of foreign flagged vessels as a matter of “comity” – courteous recognition accorded by one nation to the laws and institutions of another.  So unless you attract the attention of the authorities for example because your boat is deemed not to be seaworthy, you will generally be allowed to go about your business as a visitor without hindrance.

There are some elements of Coastal State Law that a visiting boat may be asked to comply with and it is these regulations that the RYA does its best to keep abreast of.  The most common is for the skipper of the vessel to be required to prove that he or she is competent to be in command of the vessel.

A country may specify requirements such as a crew list or specific publications that must be carried (e.g. a local almanac / International regulations for preventing collisions at sea). Vessels navigating the European inland waters are generally required to carry a copy of the local rules (which may be written in the native language of the country concerned). It is important to ensure you are aware of all such requirements.
 
RYA Members will find country by country information for some of the more commonly visited countries under Boating Abroad for Members. 

It is not in the RYA’s normal scope of work to advise on matters relating to boats that are kept abroad, residency in foreign countries or trading matters abroad. If you choose to base your boat abroad, have both property and your boat in a country, become resident abroad,  cruise a company owned yacht or use your vessel for commercial gain (including offering it for charter), the rules may differ considerably from those for vessels on short visits. 

Different countries and even local areas within countries will have their own regulations. It is essential that you find out what these are, as failure to pay taxes for example can result in significant fines when the authorities become aware of your non-payment. Not knowing the regulations is no defence for non-compliance and you may find that in addition to the national regulations there are local variations or applications you need to be aware of. To do this you will need to contact the relevant national and local authorities.