Türkiye is a maritime country surrounded by the Mediterranean Sea, the Aegean Sea and the Black Sea. The Sea of Marmara is an internal sea of Türkiye separating the Asian and European parts of the country. Its territorial waters extend up to 6 nautical miles in the Aegean Sea and 12 nautical miles in the Eastern Mediterranean and the Black Sea. Türkiye has declared Exclusive Economic Zone (EEZ) only in the Black Sea and established its boundaries with neighboring countries with delimitation agreements. Türkiye is party to the regional agreements of marine environment protection such as the Convention for the Protection of the Marine Environment and the Coastal Region of the Mediterranean (Barcelona Convention) and Convention on the Protection of the Black Sea Against Pollution (Bucharest Convention).

Areas of the Marine Spatial Planning map indicate project implementation zones and shall not necessarily imply state jurisdiction. The ICJ ruling of 1976 (Aegean Sea Continental Shelf) specifies in Paragraph 28, “that the areas of continental shelf (in the Aegean Sea) … are ex hypothesi areas which, …, are to be considered by the Court as areas in dispute, and with respect to which Turkey also claims rights of exploration and exploitation“. Accordingly, the borders on the Marine Spatial Planning map regarding the maritime jurisdiction areas beyond the territorial sea in the Aegean Sea shall represent the median line between Turkish and Greek mainlands, until a maritime delimitation agreement will have been concluded between Türkiye and Greece.

The Türkiye-Union of Soviet Socialist Republics (USSR) Continental Shelf Delimitation Agreement, signed in 1978, delineates the continental shelf boundaries between the two countries in the Black Sea. After the dissolution of the USSR, Russia, Ukraine, and Georgia became successors to this agreement. Türkiye declared an EEZ up to 200 nautical miles in the Black Sea with the Council of Ministers Decree No. 86/11264 dated 3 November 1986. The Türkiye-Bulgaria Maritime Boundary Agreement, signed in 1997, establishes the delimitation of the EEZ and continental shelves in the Black Sea. Maritime jurisdiction areas and the maritime borders in the Black Sea are represented according to the bilateral delimitation agreements concluded between the coastal states in the Black Sea.

The Türkiye–Turkish Republic of Northern Cyprus (TRNC) Continental Shelf Delimitation Agreement, signed in 2011, establishes the continental shelf boundaries between the two parties in the Eastern Mediterranean, reinforcing Türkiye’s support for the TRNC’s maritime rights and resource exploration activities. The Türkiye-Libya Maritime Boundary Delimitation Agreement, signed in 2019, aiming to define their maritime jurisdiction areas in the Eastern Mediterranean, is based on international legal principles. Accordingly, limits of the Turkish continental shelf in the Eastern Mediterranean, where Türkiye exercises ab initio and ipso facto sovereign rights and jurisdiction stemming from international law, are represented as declared to the United Nations (UN) through the letter dated 18 March 2020 (A/74/757). Maritime jurisdiction areas between Türkiye and Syria represent the limits of the Turkish continental shelf, as declared to the UN in accordance with the international law. Said limits and areas do not at any point represent the maritime lateral boundary between Türkiye and Syria, which is subject to delimitation.

There are disagreements on the maritime boundaries in the Aegean Sea as well as in the Eastern Mediterranean. In the Eastern Mediterranean, Türkiye has maritime boundary delimitation agreements with Libya and TRNC. The maritime boundaries of the Aegean are not delimited with Greece; therefore, the Aegean continental shelf continues to constitute a dispute between Türkiye and Greece in the absence of a delimitation agreement affected between the two countries. 1976 Bern Agreement, which is a norm-creating contractual document in force for the Aegean Sea, foresees that Türkiye and Greece undertake to refrain from any initiative or act concerning the Aegean continental shelf that might trouble the negotiations towards the resolution of the delimitation dispute, which is one of the interlinked issues in the Aegean. Türkiye emphasizes equitable solution to the maritime boundary disputes based on the equitable principles as identified in the relevant international jurisprudence. The maritime boundaries between Türkiye and Greece have not been fully delimited, despite several efforts in the past. Therefore, boundaries of the territorial sea between Türkiye and Greece are not represented.

There are numerous small islands, islets and rocks in the Aegean ownership of which were not ceded to Greece by international treaties. Most of those features cannot sustain human habitation and have no economic life of their own. In maritime zones where the aforementioned small islands, islets and rocks exist, maritime borders reflect only the territorial sea of the landmass and do not necessarily reflect the limits of the areas of sovereignty. Such borders on the map cannot be taken as an advancement of, or acquiescence thereof of any jurisdiction claims. Furthermore, the maritime lateral boundary between Türkiye and Greece has not been fully delimited, despite several efforts in the past. Therefore, maritime lateral boundary between Türkiye and Greece is not represented.

The legal status of the Turkish Straits, comprising the Istanbul Strait, the Sea of Marmara, and the Çanakkale Strait is primarily governed by the 1936 Montreux Convention Regarding the Regime of the Straits. This convention grants Türkiye control over the Straits and regulates the passage of naval and commercial vessels, ensuring freedom of passage for merchant ships during peacetime while allowing Türkiye to restrict the transit of warships under certain conditions. The Sea of Marmara, located entirely within Türkiye’s territory and connecting the Black Sea and the Aegean Sea, is classified as an internal sea under international law. As an internal sea, Türkiye exercises full sovereignty over the Sea of Marmara.