Can Iran Close the Strait of Hormuz? A Legal and Geopolitical Analysis

The Strait of Hormuz remains one of the most strategically vital maritime choke points in the world. Linking the Persian Gulf to the Arabian Sea and onward to the high seas, it is bordered by Iran and Oman. Roughly 20 percent of global crude oil and a significant portion of liquefied natural gas pass through this narrow waterway each day. Amid escalating tensions involving Iran, Israel and the United States in the Gulf region, a recurring legal question has resurfaced: Can Iran lawfully close the Strait of Hormuz?

This issue must be assessed not only through treaty law but also in light of contemporary geopolitical realities, where major powers themselves have at times stretched or challenged international legal norms.

The Legal Framework: UNCLOS and Transit Passage

Under the 1982 United Nations Convention on the Law of the Sea (UNCLOS), the Strait of Hormuz is classified as a strait used for international navigation. Articles 38 and 44 establish the regime of transit passage. All ships and aircraft, including military vessels, enjoy the right of continuous and expeditious passage without prior authorization from coastal states.

Crucially, this right of transit passage may not be suspended, even during periods of tension or conflict. This principle does not apply exclusively to Iran. It equally governs other strategic straits such as the Strait of Malacca and the Strait of Singapore. Malaysia and Indonesia exercise sovereignty over the Strait of Malacca, while Malaysia, Indonesia and Singapore share responsibility over the Strait of Singapore. None of these littoral states may unilaterally close these waterways to international navigation.

Current Situation and Threats

As of March 14, 2026, tensions remain high following a two-week war between Iran and the United States and Israel. President Trump has issued an ultimatum to Iran, threatening to destroy Iran’s oil processing infrastructure if the country continues blocking the Strait of Hormuz. Iran had previously threatened to attack US oil interests in the region if its energy infrastructure were bombed. US missiles struck Iranian air defenses on Kharg Island, a key location for oil processing, but Trump refrained from targeting the oil infrastructure itself, reserving the right to reconsider that decision if the Strait is blocked.

Reports indicate that Iran has been actively attempting to disrupt shipping through the strait, with over 1,000 cargo ships blocked since the outbreak of the conflict. There are also reports of Iran mining the waterway. Despite these actions, some vessels, such as the Liberia-flagged tanker Shenlong Suezmax, have managed to transit the strait.

Geopolitical Implications and Potential Responses

The Strait of Hormuz is approximately 104 miles long and varies in width from 60 miles to 24 miles. Its narrowest point is 21 nautical miles wide, making it vulnerable to disruption. The strait separates Iran from the Musandam Governorate of Oman and the United Arab Emirates.

President Trump has stated that “many countries” will send warships to help open the Strait of Hormuz, specifically mentioning China, France, Japan, South Korea, and the UK. However, the implementation of naval escorts has yet to materialize. The potential for escalation remains high, with any attempt to forcibly open the strait carrying significant risks.

Key Takeaways

• Under international law (UNCLOS), Iran cannot legally close the Strait of Hormuz to international navigation.
• Iran is currently attempting to disrupt shipping through the strait as a form of leverage in the ongoing conflict.
• The United States has threatened military action if Iran continues to block the waterway.
• The situation remains volatile, with the potential for significant disruption to global oil supplies.