Legal Definitions - right of innocent passage

The right of innocent passage is a fundamental principle in international maritime law that allows ships of all states to navigate freely and continuously through the territorial waters of another sovereign state, provided their passage is "innocent." For passage to be considered innocent, it must not be prejudicial to the peace, good order, or security of the coastal state.

This means the ship must refrain from any activities that could be deemed a threat or a violation of the coastal state's laws and regulations, such as:

• Any threat or use of force against the coastal state.
• Weapons exercises or practice.
• Acts aimed at collecting information to the prejudice of the defense or security of the coastal state (spying).
• Launching, landing, or taking on board any aircraft or military device.
• Serious and willful pollution.
• Fishing activities.
• Carrying out research or survey activities.
• Any other activity not having a direct bearing on passage.

While coastal states have sovereignty over their territorial waters, they cannot impede or hamper innocent passage, though they can enact laws to regulate it, such as specifying sea lanes or traffic separation schemes. Submarines and other underwater vehicles are required to navigate on the surface and show their flag during innocent passage.

Here are some examples:

• Commercial Cargo Ship: A large container ship, registered in Panama, is transporting goods from Singapore to Rotterdam. To reach its destination efficiently, its planned route takes it through the territorial waters of Sri Lanka, a coastal state. As the ship is simply transiting, maintaining a steady course and speed, and not engaging in any fishing, military drills, or unauthorized research within Sri Lankan waters, its movement constitutes an exercise of the right of innocent passage. Sri Lanka, despite its sovereignty over these waters, cannot legally prevent the ship from passing through, provided the passage remains non-threatening and adheres to international maritime regulations.

• Passenger Ferry: A passenger ferry regularly operates between two islands belonging to different nations, "Island A" and "Island B." Part of its journey requires it to pass through a narrow strait that falls entirely within the territorial waters of a third country, "Coastal Nation C." The ferry, carrying tourists and local commuters, simply navigates through this strait without stopping, deploying fishing nets, or conducting any activities that could threaten Coastal Nation C's security or resources. This transit is an example of the right of innocent passage, and Coastal Nation C must allow the ferry to proceed unhindered, even though the waters are sovereign territory.

• Foreign Naval Vessel: A warship belonging to the navy of "Country X" needs to travel from its home port to participate in a joint exercise with an allied nation. Its most direct route involves passing through the territorial waters of "Country Y," a neutral state. The warship proceeds through Country Y's waters on the surface, with its national flag displayed, and refrains from any activities such as weapons practice, surveillance, or launching aircraft. Because its passage is continuous, expeditious, and poses no threat to Country Y's peace, good order, or security, it is exercising the right of innocent passage. Country Y cannot block its transit, but the warship must strictly adhere to the conditions of innocent passage, including surfacing if it were a submarine.