The concepts of territorial sea and inland waters are fundamental to the Law of the Sea, defining the extent of a coastal state's sovereignty over adjacent maritime areas. While both fall under the coastal state's jurisdiction, they differ significantly in their legal status and the rights of other states within them.

1. Inland Waters:

• Definition: Inland waters are all waters on the landward side of the baseline from which the breadth of the territorial sea is measured. This includes rivers, lakes, internal seas, ports, harbors, roadsteads, and waters within bays and estuaries that are considered part of the landmass.
• Sovereignty: A coastal state exercises full and complete sovereignty over its inland waters, identical to its sovereignty over its land territory. This means the coastal state has absolute control, and foreign vessels generally have no right of entry or passage without the express permission of the coastal state.
• Right of Passage: There is no right of innocent passage for foreign vessels in inland waters. Entry is a privilege, not a right, and is subject to the coastal state's laws and regulations.

2. Territorial Sea:

• Definition: The territorial sea is a belt of coastal waters extending seaward from the baselines of the coastal state. It is the immediate maritime zone adjacent to the land territory and inland waters.
• Sovereignty: A coastal state exercises sovereignty over its territorial sea, including the airspace above it, as well as its seabed and subsoil. This sovereignty is, however, not absolute.
• Right of Passage: The key distinction is that the sovereignty over the territorial sea is subject to the right of 'innocent passage' for foreign vessels. Innocent passage means navigation through the territorial sea that is not prejudicial to the peace, good order, or security of the coastal state. Submarines are required to navigate on the surface and show their flag.

Key Distinctions:

| Feature | Inland Waters | Territorial Sea | | :---------------- | :------------------------------------------------- | :--------------------------------------------------- | | Location | Landward side of the baseline | Seaward from the baseline | | Sovereignty | Full and absolute, same as land territory | Full, but subject to the right of innocent passage | | Right of Passage | No right of innocent passage for foreign vessels | Right of innocent passage for foreign vessels exists | | Examples | Rivers, lakes, ports, harbors, internal bays | The maritime belt immediately adjacent to the coast |

Breadth of Territorial Sea that is Internationally Accepted:

Historically, the breadth of the territorial sea was a contentious issue, with claims ranging from 3 nautical miles (the 'cannon-shot rule') to much wider belts. This lack of uniformity led to numerous disputes and uncertainties in international relations.

However, the United Nations Convention on the Law of the Sea (UNCLOS), adopted in 1982, largely resolved this issue and is now widely accepted as the foundational legal framework for maritime zones. UNCLOS established a standardized and internationally recognized breadth for the territorial sea.

According to Article 3 of UNCLOS, every State has the right to establish the breadth of its territorial sea up to a limit not exceeding 12 nautical miles, measured from baselines determined in accordance with the Convention. This 12-nautical-mile limit is now the universally accepted standard for the territorial sea. Within this zone, the coastal state exercises sovereign rights over the waters, the airspace above, the seabed, and its subsoil, subject only to the right of innocent passage for foreign vessels.