Terminate the unrestricted passage of the Russian Navy in the Gulf of Finland — restore Estonia’s full maritime boundary.

Military threat: Russia uses the six-nautical-mile international corridor for the unrestricted movement of its naval forces in the Baltic Sea, supporting its aggression against Ukraine. Russian warships can maneuver freely without falling under Estonian or Finnish control. In 2025, Russian Su-35 fighters violated Estonian airspace while shielding their “shadow fleet” tankers.

Shadow fleet problem: Sanctioned Russian oil tankers use the corridor, posing environmental risks to the Baltic Sea. Many lack valid flag-state registration and adequate insurance. Russia protects these vessels with military aircraft.

Airspace incursions: Restoring the territorial sea would entitle Estonia to prohibit overflights by Russian military aircraft over its maritime area, reducing airspace violations and provocations.

Infrastructure risks: Damage to the Balticconnector and other subsea cables shows that the current system does not provide sufficient control over strategic assets.

Breach of a constitutional principle: Under Section 2 of the Constitution, territorial waters are part of the state “as an integral and indivisible whole.” Voluntarily relinquishing the full breadth of territorial waters weakens Estonia’s sovereignty.

1. Termination of the agreement Adopt a law to denounce the 1993–1994 arrangement with 12 months’ notice to Finland, as provided in the treaty.

2. Restoration of the full maritime boundary Establish Estonia’s territorial sea to a breadth of 12 nautical miles in accordance with UNCLOS Article 3 along the entire Estonian coastline, including towards the Gulf of Finland.

3. Automatic junction with Finland’s territorial sea Finland did not abandon the full breadth of its territorial sea; it only limited it in the central part, keeping at least three nautical miles from the median line. Estonia’s restored territorial sea will automatically join Finland’s existing territorial sea in many locations (especially in the western and eastern sectors) where the gulf is less than 24 nautical miles wide. This means the international corridor will partially disappear even without Finland’s consent.

4. Stronger maritime and air control Apply to all foreign vessels, especially warships: • Mandatory 48-hour prior notification • Documentary compliance checks (valid flag, insurance) • Right to deny passage on security grounds • Prohibition of overflights by military aircraft over the territorial sea

5. Legal clarity within the UNCLOS framework The Gulf of Finland does NOT connect two distinct seas (it connects the Baltic Sea with the Baltic Sea) and therefore does not qualify as an “international strait” under UNCLOS Article 37. This means Russia has NO right to claim “transit passage,” and only the “innocent passage” regime applies, with all attendant limitations.

6. Coordination with Finland Propose a joint initiative with Finland to restore the full maritime boundary, strengthening both countries’ positions and completely eliminating the international corridor.

Practical impact: Even a unilateral step yields results: • The international corridor will shrink significantly • Improved control over the “shadow fleet” in many areas • Reduced maneuvering space for the Russian Navy • A stronger starting position for negotiations with Finland

Legal basis: • UNCLOS Article 3 guarantees every state the sovereign right to a 12-nautical-mile territorial sea • UNCLOS Article 37 does NOT apply to the Gulf of Finland • No consent is required from Finland, any third state, the UN, or the International Maritime Organization. Under UNCLOS, each coastal state determines its territorial sea independently; a unilateral decision with proper notification is fully valid and does not require approval from other states or organizations.

Conclusion: Estonia’s security must not depend on an agreement concluded 30 years ago. Even a unilateral step will deliver substantial results and demonstrate to other states that Estonia actively defends its sovereignty.