In maritime governance, three types of state authority—Flag State, Port State, and Coastal State—play crucial roles in enforcing international maritime laws. Understanding their functions is essential to grasp how global maritime regulations are applied and upheld.

🚩 1. Flag State

Definition:
The Flag State is the country in which a ship is registered and whose flag it flies.

Responsibilities:

• Enforce international conventions (e.g., SOLAS, MARPOL, STCW) on their registered vessels

• Conduct ship inspections and issue necessary certificates

• Ensure ships are properly constructed, maintained, and crewed

• Investigate accidents involving their flagged vessels

Example:
A ship flying the flag of Panama must comply with all international obligations as enforced by the Panamanian maritime authority—even when sailing in international waters.

⚓ 2. Port State

Definition:
The Port State is the country where a foreign ship docks or anchors in one of its ports.

Responsibilities:

• Conduct inspections of foreign ships for compliance with international standards (Port State Control)

• Detain ships that fail to meet safety, environmental, or crew welfare requirements

• Work through regional agreements (e.g., Paris MoU, Tokyo MoU) for coordinated inspections

Example:
A Liberian-flagged ship docking in Singapore may be inspected by Singaporean authorities for MARPOL and STCW compliance.

🏖️ 3. Coastal State

Definition:
The Coastal State is a country whose coastline borders the waters in which a ship is operating.

Jurisdiction Includes:

• Territorial Sea (up to 12 nm): Full sovereignty, including enforcement of customs, environmental, and safety laws

• Contiguous Zone (12–24 nm): Enforcement of specific laws (customs, immigration, sanitary)

• Exclusive Economic Zone (EEZ, up to 200 nm): Rights to exploit marine resources and enforce environmental protection

Example:
If a vessel pollutes within the EEZ of Australia, Australian authorities may take enforcement action under UNCLOS and MARPOL.

⚖️ Why These Roles Matter

Together, Flag, Port, and Coastal States form a layered system of regulatory enforcement:

• Flag States ensure ships are properly regulated from the point of registration.

• Port States act as checkpoints for international compliance.

• Coastal States protect their waters and resources from illegal or harmful activities.

🧭 Summary

These three state roles are essential in maintaining maritime order, safety, and environmental responsibility. Their cooperation helps ensure that the world’s ships operate under consistent and effective legal standards, no matter where they sail.