Territorial Sea or Territorial Water

What is Territorial Sea?
What is Contiguous Zone?
Delimitation of the territorial sea between States with opposite or adjacent coasts.
Legal status of the territorial sea, of the air space  over the territorial sea and of its bed and subsoil
Rights of Other States on Territorial Sea.
Duties and Rights of Coastal State on Territorial Sea. 

Territorial Sea or Water

Territorial waters or a territorial sea as defined by the 1982 United Nations Convention on the Law of the Sea, is a belt of coastal waters extending at most 12 nautical miles (22.2 km; 13.8 mi) from the baseline (usually the mean low-water mark) of a coastal state. The territorial sea is regarded as the sovereign
territory of the state, although foreign ships (civilian) are allowed innocent passage through it, or transit passage for straits; this sovereignty also extends to the airspace over and seabed below. Adjustment of these boundaries is called, in international law, maritime delimitation.

According to Article 3 of United Nations Convention on Law of The Sea (UNCLOS) III

Every State has the right to establish the breadth of its territorial sea upto  a  limit  not  exceeding  12  nautical  miles,  measured  from  baselines determined in accordance with this Convention.

If this would overlap with another state's territorial sea, the border is taken as the median point between the states' baselines, unless the states in question agree otherwise. A state can also choose to claim a smaller territorial sea.




Delimitation of the territorial sea between States with opposite or adjacent coasts

According to Article 15 of United Nations Convention on Law of The Sea (UNCLOS) III

Where the coasts of two States are opposite or adjacent to each other, neither of the two States is entitled, failing agreement between them to the contrary, to extend its territorial sea beyond the median line every point of which is equidistant from the nearest points on the baselines from which the
breadth  of  the  territorial  seas  of  each  of  the  two  States  is  measured.    The above provision does not apply, however, where it is necessary by reason of historic title or other special circumstances to delimit the territorial seas of the two States in a way which is at variance therewith.

Legal status of the territorial sea, of the air space  over the territorial sea and of its bed and subsoil

According to Article  of United Nations Convention on Law of The Sea (UNCLOS) III

1. The sovereignty of a coastal State extends, beyond its land territory and internal waters and, in the case of an archipelagic State, its archipelagic waters, to an adjacent belt of sea, described as the territorial sea.

2. This sovereignty extends to the air space over the territorial sea as well as to its bed and subsoil.

3. The sovereignty over the territorial sea is exercised subject to this Convention and to other rules of international law.

Contiguous zone

According to Article 33 of United Nations Convention on Law of The Sea (UNCLOS) III

1. In a zone contiguous to its territorial sea, described as the contiguous zone, the coastal State may exercise the control necessary to:

(a)   prevent  infringement  of  its  customs,  fiscal,  immigration  or sanitary laws and regulations within its territory or territorial sea;

(b)  punish   infringement   of   the   above   laws   and   regulations committed within its territory or territorial sea.

2. The contiguous zone may not extend beyond 24 nautical miles from the baselines from which the breadth of the territorial sea is measured.

Rights of Other States on Territorial Sea

Right of innocent passage

According to Article 17 of United Nations Convention on Law of The Sea (UNCLOS) III

Subject  to  this  Convention,  ships  of  all  States,  whether  coastal  or land-locked, enjoy the right of innocent passage through the territorial sea.



Submarines and other underwater vehicles

According to Article 20 of United Nations Convention on Law of The Sea (UNCLOS) III

In  the  territorial  sea,  submarines  and  other  underwater  vehicles  are required to navigate on the surface and to show their flag.


Foreign nuclear-powered ships 

According to Article 23 of United Nations Convention on Law of The Sea (UNCLOS) III

Foreign  nuclear-powered  ships  and  ships  carrying  nuclear  or  other inherently dangerous or noxious substances shall, when exercising the right of innocent passage through the territorial sea, carry documents and observe special precautionary measures established for such ships by international
agreements.

Duties and Rights of Coastal States on Territorial Sea

Duties of the coastal State
 
According to Article 24 of United Nations Convention on Law of The Sea (UNCLOS) III

1. The coastal State shall not hamper the innocent passage of foreign ships through the territorial sea except in accordance with this Convention. In  particular,  in  the  application  of  this  Convention  or  of  any  laws  or regulations  adopted  in  conformity  with  this  Convention,  the  coastal  State shall not:

(a)   impose requirements on foreign ships which have the practical effect of denying or impairing the right of innocent passage; or

(b)  discriminate in form or in fact against the ships of any State or against  ships  carrying  cargoes  to,  from  or  on  behalf  of  any State.

2. The coastal State shall give appropriate publicity to any danger to navigation, of which it has knowledge, within its territorial sea.


Rights of protection of the coastal State

According to Article 25 of United Nations Convention on Law of The Sea (UNCLOS) III

1. The coastal State may take the necessary steps in its territorial sea to prevent passage which is not innocent.

2. In the case of ships proceeding to internal waters or a call at a port facility outside internal waters, the coastal State also has the right to take the necessary steps to prevent any breach of the conditions to which admission of those ships to internal waters or such a call is subject.

3. The  coastal  State  may,  without  discrimination  in  form  or  in  fact among foreign ships, suspend temporarily in specified areas of its territorial sea the innocent passage of foreign ships if such suspension is essential for the protection of its security, including weapons exercises.  Such suspension
shall take effect only after having been duly published.


Charges which may be levied upon foreign ships

According to Article 26 of United Nations Convention on Law of The Sea (UNCLOS) III

1. No charge may be levied upon foreign ships by reason only of their passage through the territorial sea.

2. Charges  may  be  levied  upon  a  foreign  ship  passing  through  the territorial  sea  as  payment  only  for  specific  services  rendered  to  the  ship. These charges shall be levied without discrimination.