Who Controls the Strait of Hormuz? International Law, UNCLOS & Sovereignty Explained

The question of who controls the Strait of Hormuz is not merely academic — it is one of the most consequential and actively contested legal disputes in international maritime law. The answer depends on whether you are asking about de jure legal authority (what international law says) or de facto military reality (who can actually impose their will on ships transiting the waterway).

The Legal Answer: No Single Nation Controls the Strait

Under international law, the Strait of Hormuz is not owned or controlled by any single state. The navigable shipping lanes pass through the territorial waters of two nations:

• Iran controls the northern half of the Strait (Hormozgan Province coastline, including Qeshm Island and Bandar Abbas)
• Oman controls the southern half (the Musandam Peninsula), through whose territorial waters virtually all commercial shipping actually transits

However, because the Strait is an internationally recognized waterway used for navigation between two high seas areas (the Persian Gulf and the Gulf of Oman), it is subject to special legal rules that override normal territorial sea sovereignty — specifically, the UNCLOS regime of transit passage.

UNCLOS and Transit Passage: The Legal Framework

The United Nations Convention on the Law of the Sea (UNCLOS), ratified by 168 nations, establishes a specific legal regime for “straits used for international navigation” under Part III, Articles 34–45.

Article 37: Scope

The transit passage regime applies to “straits which are used for international navigation between one area of the high seas or an exclusive economic zone and another area of the high seas or an exclusive economic zone.” The Strait of Hormuz fits this definition precisely — it connects the Persian Gulf (semi-enclosed sea with high seas rights) to the Gulf of Oman (open ocean).

Article 38: Right of Transit Passage

Under Article 38, all ships and aircraft enjoy the right of transit passage, defined as “the exercise of freedom of navigation and overflight solely for the purpose of continuous and expeditious transit.” The critical provision: transit passage may not be suspended by the bordering states — not for security reasons, not during armed conflict, not for any reason.

What Transit Passage Guarantees

• Surface warships of any nation may transit continuously
• Submarines may transit in their normal mode (i.e., submerged — unlike innocent passage, which requires surfacing)
• Military aircraft may fly over the strait
• No prior notification or permission is required from the coastal states
• The coastal state cannot suspend or restrict transit for any reason

Iran’s Counter-Argument: Innocent Passage vs. Transit Passage

Iran takes a fundamentally different legal position. Tehran argues that transit passage does not apply to the Strait of Hormuz, and that only the older, more restrictive regime of innocent passage governs. Here is why this distinction matters enormously:

Iran’s legal argument is based on two facts: first, Iran signed but never ratified UNCLOS, meaning it is not formally bound by Articles 37–38. Second, Iran argues that a 1982 bilateral agreement between Iran and Oman created a special regime for the Strait that supersedes UNCLOS.

The international community — including the United States, European Union, and the vast majority of maritime nations — overwhelmingly rejects Iran’s interpretation. The U.S. Navy operates under rules of engagement that treat the transit passage right as absolute and enforceable by force if necessary.

The Military Reality: De Facto Control

Legal rights and military reality are two different things. Iran’s de facto ability to disrupt Strait transit derives not from legal authority but from its physical proximity and military assets:

• Bandar Abbas — Iran’s main naval base — sits directly on the Strait’s narrowest point
• IRGC fast-attack fleets can reach any point in the Strait within minutes
• Coastal missile batteries on the Zagros mountains have the entire Strait within range
• Iran can deploy naval mines faster than they can be cleared

The 2026 crisis demonstrated this asymmetry clearly. Iran cannot legally close the Strait, but it demonstrated it can physically disrupt transit to the point of near-total shutdown for weeks — imposing massive economic costs on the entire global economy while absorbing whatever military response the U.S. chooses to deploy.

The U.S. Fifth Fleet: Legal Enforcer of Transit Passage

The U.S. Navy’s Fifth Fleet, headquartered in Manama, Bahrain, exists primarily to enforce the transit passage right. Its presence — typically two Carrier Strike Groups, multiple destroyers and frigates, mine countermeasure vessels, and logistics ships — represents the physical guarantee behind the legal framework.

The Fifth Fleet’s standing orders regarding the Strait: ensure freedom of navigation for all commercial and military vessels, per UNCLOS transit passage rights, using kinetic force if necessary. This is not a theoretical commitment — U.S. forces have used force to enforce these rights before, most notably during Operation Praying Mantis in 1988, when the U.S. Navy sank half of Iran’s operational surface fleet in a single day following Iranian mine attacks on U.S.-flagged vessels.

Has Iran Ever Successfully Closed the Strait?

Iran has never succeeded in permanently closing the Strait, but has achieved significant temporary disruptions:

• 1984–1988 (Tanker War): Attacked ~546 commercial vessels; U.S. intervention via Operation Earnest Will and Operation Praying Mantis restored passage
• 2019–2021: Series of tanker seizures, limpet mine attacks, and drone strikes created sustained elevated risk but did not close the Strait
• 2026 Blockade: The most severe disruption — transit reduced to 5% of normal for several weeks before ceasefire and U.S. MCM operations began restoring access

FAQ: Who Controls the Strait of Hormuz?

Can Iran legally close the Strait of Hormuz?

Under UNCLOS transit passage doctrine (Articles 37–38), no. The Strait qualifies as an international navigation strait and all ships have irrevocable transit rights. Iran disputes this but has never ratified UNCLOS, and the international community universally rejects Tehran’s alternative “innocent passage” argument.

Has Iran ever closed the Strait of Hormuz?

Never permanently. The closest it came was the 2026 conflict, when mine deployments and vessel seizures reduced transit to 5% of peacetime levels for several weeks — the most severe disruption in the waterway’s modern history.

Does Oman have a role in keeping the Strait open?

Yes — a critical one. Since the shipping lanes run through Omani territorial waters, Oman’s political neutrality is essential. Oman has maintained diplomatic relations with Iran throughout every regional crisis, serving as a quiet back-channel for negotiations. Without Omani cooperation, operating the TSS would be legally and practically far more complex.