UNCLOS – Law of the Sea

It is all about territorial waters; The United Nations Convention on the Law of the Sea (UNCLOS), an international agreement which defined the limits, their right and responsibilities of the nation’s towards their territorial water. It is sea treaty which establishes the rules for the use of the high seas for international navigation.

UNCLOS conferences and Conventions:

Three “UNCLOS” conferences have been convened: UNCLOS I, at Geneva in 1958; UNCLOS II, at Geneva in 1960; and UNCLOS III, at Geneva in 1974. The outcome of UNCLOS III was the United Nations Convention on the Law of the Sea (catalogued by HMSO as Cmnd. 8941), commonly known as “UNCLOS”.


  • Attempts to codify the international law of the sea.
  • Is a treaty document of 320 articles and 9 annexes, governing all aspects of ocean space, such as delimitation, environmental control, marine scientific research, economic and commercial activities, transfer of technology and the settlement of disputes relating to ocean matters.
  • Came into force internationally on 16 November 1994.

UNCLOS provisions relating to zones of coastal State jurisdiction and the High Seas


  • UNCLOS sets the width of the territorial sea at 12 nautical miles, with a contiguous zone at 24 nautical miles from the baseline. It defines innocent passage through the territorial sea and defines transit passage through international straits. It defines archipelagic States and allows for passage through archipelagic waters.
  • UNCLOS establishes exclusive economic zones (EEZs) extending to 200 nautical miles from baselines. It defines the continental shelf and extends jurisdiction over the resources of the shelf beyond 200 miles where appropriate.
  • UNCLOS defines the legal status of the high seas and establishes regulations for the control of marine pollution.
  • States in dispute about their interpretation of UNCLOS may submit their disagreements to competent courts such as the International Court of Justice (in The Hague), or the Law of the Sea Tribunal (in Hamburg).
  • For notes on the different zones of coastal State jurisdiction, and on the high seas see H01e.

UNCLOS provisions relating to port State, coastal State and flag State control of shipping

  • Responsibility for enforcement of regulations rests mainly with flag States, but as vessels enter zones closer to the coast the influence of coastal State jurisdiction and, ultimately, port State jurisdiction, gradually increases.
  • Article 94 deals with duties of the flag State, while Article 217 deals with enforcement by flag States
  • Article 218 deals with port State jurisdiction. When a vessel is voluntarily within a port or at an offshore terminal, the port State may, where the evidence warrants, begin proceedings in respect of discharges in violation of international rules (i.e. regulations in MARPOL 73/78). Another State in which a discharge violation has occurred, or the flag State, may request the port State to investigate the violation.
  • Article 200 deals with coastal State jurisdiction as applied in relation to pollution provisions. Where there are clear grounds for believing that a vessel navigating in the territorial sea of a State has violated laws and regulations of the coastal State adopted in accordance with UNCLOS or applicable international pollution regulations, the coastal State may inspect the vessel and, where evidence warrants, institute proceedings including detention of the vessel. Vessels believed to have violated pollution laws in an EEZ may be required to give identification and voyage information to the coastal State.

UNCLOS provisions relating to pollution prevention

  • States must agree international rules and standards to prevent pollution from vessels (Article 211). (This obligation is currently met by MARPOL 73/78.)
  • Coastal States may also promulgate and enforce pollution regulations in their own EEZs which may, in some circumstances, include imposition of routeing restrictions.
  • In the territorial sea additional navigational restraints (e.g. traffic separation schemes and sea lanes) may be imposed on vessels with dangerous and hazardous cargoes.
  • Coastal States and ports may make entry to internal waters and harbours conditional on meeting additional pollution regulations.


  • The MS (Prevention of Pollution) (Law of the Sea Convention) Order 1996 (SI 1996/282) enables UK regulations to be made .
  • implementing provisions in UNCLOS 1982 (Cmnd. 8941) relating to pollution of the sea by ships; and
  • Relating to the protection and preservation of the marine environment from pollution from ships caused beyond the UK’s territorial sea.
  • The MS (Prevention of Pollution) (Limits) Regulations 1996 (SI 1996/2128) and the MS (Prevention of Pollution) (Limits) Regulations 1997 (SI 1997/506), which were made under powers conferred by the above Order, specify sea areas, called “controlled waters”, within which the jurisdiction and rights of the UK are exercisable in accordance with part XII of UNCLOS for the protection and preservation of the marine environment, i.e. in order to prevent pollution by discharges from ships. For a notes on controlled waters ..

To be continued………

References: Articles from IMLI (International Maritime law institute)

The Shipmaster’s BUSINESS COMPANION (By Mr. Malcolm Maclachlan) …

Contributed by: Prashant Kumar, The Author has over 17 years of experience in shipping, presently working as Deputy Technical Manager. The views are his own and do not represent his employer.


Categories: Crew matters, Regulations

Tags: , ,

1 reply

  1. The law of sea and its history is really interesting, even after the clear convenstions, many neighbouring countries are still fighting for THEIR 200nm. In Gulf of Mexico US, Cuba and Mexico had agreed for their sea line and it is one of the best example of agreement.


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