Innocent Passage under UNCLOS

Innocent passage is the right of foreign ships to travel through a country's territorial sea without engaging in activities that threaten the coastal State's peace, good order or security. Under the United Nations Convention on the Law of the Sea (UNCLOS), 1982, this right balances international navigation with the coastal State's sovereignty over its territorial sea.

Where the right applies

A coastal State may establish a territorial sea extending up to 12 nautical miles from baselines determined under UNCLOS. Although this sea falls under its sovereignty, Article 17 gives ships of all States, whether coastal or landlocked, the right of innocent passage, subject to the Convention.

• The right concerns navigation by ships; it does not confer a corresponding right of overflight on aircraft.

What counts as passage

Article 18 covers navigation across the territorial sea without entering internal waters, as well as navigation to or from internal waters or a port facility.

• Passage must be continuous and expeditious, rather than an opportunity to remain in the territorial sea for unrelated activities.
• Stopping and anchoring are permitted when incidental to ordinary navigation, necessitated by force majeure or distress, or required to assist persons, ships or aircraft in danger or distress.

When passage ceases to be innocent

Under Article 19, passage is innocent only while it is not prejudicial to the coastal State's peace, good order or security and conforms to UNCLOS and other rules of international law.

• Threatening or using force against the coastal State, conducting weapons exercises, or collecting information prejudicial to its defence or security makes passage non-innocent.
• Fishing activities, research or survey activities, and acts of wilful and serious pollution contrary to UNCLOS are among the prohibited activities.
• Loading or unloading commodities, currency or persons contrary to the coastal State's customs, fiscal, immigration or sanitary laws also makes passage non-innocent.
• Under Article 20, submarines and other underwater vehicles must navigate on the surface and show their flag.

Coastal State's powers and limits

The coastal State may regulate matters such as navigation safety and environmental protection consistently with UNCLOS, but must not hamper innocent passage or discriminate against particular States' ships.

• Article 25 permits necessary steps to prevent passage that is not innocent.
• The coastal State may temporarily suspend innocent passage in specified areas when essential for its security, without discrimination; suspension takes effect only after being duly published.