Can Iran Tax Ships in Hormuz? What Global Maritime Law Says

Iran proposes charging tolls for ships in the Strait of Hormuz, a vital route for global oil trade. Tehran justifies this as payment for "safe passage," aiming to monetize its strategic control. However, the plan is highly controversial as it violates international maritime law, specifically the right of "transit passage" guaranteed under UNCLOS.

Iran’s proposal to impose toll charges on ships passing through the strategically vital Strait of Hormuz has sparked a global legal and geopolitical debate. The narrow waterway, which handles nearly one-fifth of the world’s oil and gas trade, is governed by long-established international maritime laws that prioritise free navigation. Experts argue that Tehran’s move could violate these norms and set a dangerous precedent for global trade.

What Iran Is Proposing

Amid ongoing tensions and a fragile ceasefire, Iran is considering levying transit fees on vessels crossing the Strait of Hormuz. Reports suggest that tankers could be charged significant amounts — in some cases up to millions of dollars per voyage — under the justification of providing “safe passage” through a conflict-affected region.

Iranian lawmakers have indicated that the plan is part of a broader effort to monetise the country’s strategic control over the strait. Officials argue that countries benefiting from the route for energy transport and trade should contribute financially, especially given the security challenges in the region.

This proposal comes at a time when Iran has already exercised increased control over shipping traffic, allowing selective passage and imposing conditions on vessels linked to certain countries.

What International Law Says

Under the United Nations Convention on the Law of the Sea (UNCLOS), the Strait of Hormuz is classified as an international strait. This designation is crucial because it guarantees the right of “transit passage” — meaning ships and aircraft from all nations can pass through without interference or the need to pay fees.

Legal experts emphasise that countries bordering such straits cannot block or restrict passage, nor can they impose charges simply for transit. As one analysis notes, Iran “cannot legally hamper transit passage through an international strait” under established maritime law.

Even though Iran has not formally ratified UNCLOS, many of its provisions — including freedom of navigation — are widely accepted as customary international law, making them binding in practice.

Why the Toll Plan Is Controversial

The proposal has drawn strong criticism from multiple countries and maritime experts. Critics argue that charging tolls in an international strait undermines the principle of free navigation, which is fundamental to global trade.

Global leaders have warned that allowing such a system could set a dangerous precedent. If Iran succeeds, other countries controlling key chokepoints — such as the Suez Canal or the Strait of Malacca — might attempt similar measures, potentially disrupting international commerce on a large scale.

European leaders have also pushed back strongly. Greece’s prime minister called the idea of tolls “completely unacceptable”, warning that it threatens the long-standing principle of unrestricted maritime movement.

Similarly, UK officials have argued that Iran cannot be allowed to “hijack” a vital global trade route, stressing the importance of keeping the strait open to all nations.

Practical Challenges and Enforcement Risks

Beyond legal concerns, enforcing such tolls presents major practical challenges. Many shipping companies and nations may refuse to pay, leading to potential standoffs or even military escalation.

Historically, toll systems in international straits are rare and not supported by global norms. Attempting to enforce one could lead to retaliatory actions, including naval escorts or sanctions.

At the same time, the current security situation complicates matters. With heightened military risks in the region, some ships may feel compelled to comply with Iranian demands for safe passage, even if the legality is disputed. Reports indicate that only selected vessels are currently allowed through, reflecting a de facto control mechanism already in place.

Impact on Global Trade and Energy Markets

The Strait of Hormuz is one of the world’s most critical energy corridors, with around 20% of global oil shipments passing through it. Any disruption or added cost has immediate consequences for global markets.

Analysts warn that even a small per-barrel toll could significantly increase shipping costs, particularly for large oil tankers carrying millions of barrels. This would likely push up global energy prices and add volatility to already strained supply chains.

Some estimates suggest that Iran could earn billions of dollars annually from such tolls, potentially exceeding its pre-war oil revenues.

However, the broader economic impact could be severe. Increased costs, insurance premiums, and geopolitical risks could disrupt trade flows, particularly for major energy-importing nations in Asia, including India, China, and Japan.

A High-Stakes Legal and Geopolitical Test

Iran’s proposed toll on the Strait of Hormuz is more than just an economic measure — it is a test of international law and global order. While Tehran argues that it has the right to regulate traffic through its territorial waters, most legal experts and governments maintain that international straits must remain open and free.

The outcome of this dispute could reshape maritime norms and redefine how strategic waterways are governed. If the toll system is implemented and accepted, it could weaken the long-standing principle of free navigation. If it is rejected, it may lead to further confrontation in an already volatile region.

For now, the legality of Iran’s plan remains highly contested, with global powers watching closely. As tensions continue, the Strait of Hormuz stands not just as a vital trade route, but as a flashpoint in the battle between national control and international law.