How UNCLOS works and why it fails in the Aegean Sea

What is UNCLOS

The United Nations Convention on the Law of the Sea (UNCLOS) is also called the Law of the Sea Convention or the Law of the Sea Treaty. It is an international treaty that establishes a legal framework for all marine and maritime activities. As of October 2024, 169 sovereign states and the European Union are parties. Interestingly, however, neither Turkey, Iran, Israel nor the United States have ratified this treaty.

UNCLOS is often treated as a universal framework — a rules‑based system capable of resolving maritime boundaries anywhere in the world. But the Aegean Sea exposes its limits. With hundreds of Greek islands positioned directly on Turkey’s coastline, the literal application of UNCLOS produces a map that is legally inconsistent, strategically unworkable and geographically incoherent. This article explains how UNCLOS functions in theory, and why the Aegean is the treaty’s most significant structural exception.

Why Aegean UNCLOS Is Unworkable

The Aegean Sea is one of the few maritime regions in which the literal application of the UN Convention on the Law of the Sea (UNCLOS) yields an impossible and self‑contradictory outcome. The problem is not political; it is structural. The geography itself breaks the law.

This explainer sets out the core reasons why UNCLOS cannot be applied mechanically in the Aegean, and why even UNCLOS‑supporting scholars accept that the region requires equitable adjustment.

The diagram above shows how maritime rights extend outward from a state’s coastline under UNCLOS. From the baseline, a state exercises full sovereignty over its territorial waters up to 12 nautical miles, including the airspace above. Between 12–24 nm, the contiguous zone allows limited enforcement powers. Out to 200 nm, the Exclusive Economic Zone (EEZ) grants rights to the resources in the water and on the seabed. Beyond this lies the high seas, open to all states. Beneath the surface, the continental shelf may extend beyond 200 nm where the seabed is a natural prolongation of the landmass.

Specifically, the reasons are:-

1. The Aegean’s island density makes UNCLOS collapse on contact with reality

UNCLOS assumes a normal coastline with occasional islands. The Aegean is the inverse: hundreds of Greek islands sit directly on Turkey’s coastline, some only a few kilometres away. Under UNCLOS, each island generates:

• 12 nautical miles of territorial waters

• 200 nautical miles of Exclusive Economic Zone (EEZ)

• Continental shelf rights

Applied literally, this produces a near‑continuous wall of Greek maritime zones pressed against Turkey’s mainland. The result is a geometry that no major coastal state could accept.

2. Literal UNCLOS would leave Turkey with almost no maritime space

If every Greek island received full maritime zones:

• Turkey’s Aegean coastline would shrink to narrow corridors

• Turkey’s access to the Mediterranean would depend on Greek goodwill

• Greek and Turkish territorial waters would touch at 12 nm

• The Aegean would lose its high seas entirely

This is why Turkish strategists refer to the outcome as the “Aegean cage”.

Explore: Aegean_cage_explained

3. UNCLOS was not designed for archipelagos sitting on another state’s continental shelf

UNCLOS works well for:

• Island chains far from other states

• Open seas

• Normal coastlines

It does not work when:

• One state’s islands sit directly on another state’s continental shelf

• The islands are extremely close to the mainland

• The islands are numerous enough to distort the entire maritime map

The Aegean is a legal anomaly — a geography UNCLOS never anticipated.

4. International courts already reject “Full Effect” for islands in distorted geographies

The International Court of Justice (ICJ) and the International Tribunal for the Law of the Sea (ITLOS) have repeatedly ruled that islands can be:

• Given reduced effect

• Given partial effect

• Ignored entirely

…when they distort maritime boundaries.

Key cases include Libya/Malta (1985), Romania/Ukraine (2009) and Bangladesh/Myanmar (2012). These precedents imply that UNCLOS itself cannot be applied literally in the Aegean.

5. The Aegean is too narrow for 12 nm territorial waters

If Greece extended territorial waters to 12 nm:

• Approximately 71 per cent of the Aegean would become Greek territorial sea

• Turkey’s access to international waters would shrink dramatically

• Greek and Turkish waters would touch, eliminating high seas

• Freedom of navigation — a core UNCLOS principle — would be undermined

This is why Turkey considers a 12 nm extension a casus belli: it would effectively erase the Aegean as an international sea.

6. The continental shelf beneath many Greek islands is geologically Turkish

UNCLOS recognises that continental shelves are natural prolongations of land territory. In the Aegean, many Greek islands sit on the Anatolian continental shelf. Yet literal UNCLOS would assign the shelf to Greece, even though the seabed is geologically Turkish. This is another structural contradiction.

7. The Bottom Line: UNCLOS produces a map no state could accept

If applied literally, UNCLOS would give Greece:

• Most of the Aegean

  • Most of the continental shelf

  • Strategic control over Turkey’s maritime access

  • Disproportionate rights from tiny islands

  • A veto over Turkish naval movement

This is why Turkey argues that the Aegean is “unworkable under UNCLOS”.

And it is why the Blue Homeland doctrine exists: a counter‑argument to a legal geometry Turkey sees as impossible, unjust and strategically suffocating.

Explore: Blue Homeland Explainer