Who really owns the Caspian Sea?

The Caspian Sea has been a subject of debate among Iran, Russia, Azerbaijan, Kazakhstan, and Turkmenistan for many years. The five countries bordering the sea have developed a unique legal framework governing various aspects such as navigation, territorial waters, fishing, security, and seabed resources. In 2018, the presidents of the five countries signed the Convention on the Legal Status of the Caspian Sea, which established territorial waters of up to 15 nautical miles and an exclusive fishing zone of 10 nautical miles for each country. However, the convention did not allocate specific shares of the Caspian Sea to each nation.

Prior to the dissolution of the Soviet Union in 1991, Iran and the Soviet Union were the only two countries bordering the Caspian Sea. The 1921 Russo-Persian Treaty of Friendship and the 1940 treaty regulated Iranian navigation rights, trade, and navigation. None of these agreements, however, assigned a percentage of the Caspian Sea to either Iran or the Soviet Union; instead, they focused on promoting common use rather than dividing the sea into ownership shares.

After the collapse of the Soviet Union, Azerbaijan, Kazakhstan, and Turkmenistan became independent states, transforming the bilateral legal arrangement into a five-country negotiation. Despite some Iranian politicians advocating for a 50% share, as they had previously shared the sea with the Soviet Union, no claim has been internationally recognized.

The 2018 convention created a special legal regime that separates the water, seabed, security, and resources, but it does not divide the surface into national sectors. Each country has its own territorial waters and fishing zones, while other areas remain open for common navigation. The seabed can be divided through bilateral agreements between neighboring states, which is crucial for offshore oil and gas rights.

The southern boundaries of Iran remain a sensitive issue, as Iran recently accused Ukraine of attacking an Iranian commercial vessel in the Caspian, resulting in a sailor's death. Iran views keeping external military powers away from the Caspian as a strategic priority. Iran is the only signatory that has not completed parliamentary ratification of the convention, highlighting the ongoing legal and military debates surrounding the Caspian Sea.

The Caspian Sea is not entirely a sea or a lake; it is a unique body of water with distinct characteristics. The 2018 convention acknowledges this distinction, emphasizing that the sea's resources and boundaries are subject to negotiation between neighboring states. For Iran, this means that some of its offshore resource rights, such as those in the Sardar-e Jangal area, are still subject to negotiation.

However, the central question of ownership percentages is no longer the primary issue. Instead, the focus has shifted to managing the Caspian's resources, determining maritime boundaries, and preventing external military interference.