Strait of Hormuz

The Strait of Hormuz is a narrow, natural sea passage located in the southwest of Asia, connecting the Persian Gulf with the Oman Gulf and the Arabian Sea. The strait, whose northern shores belong to Iran and southern shores to Oman, serves as a critical maritime corridor for the international transfer of energy resources from the Middle East. Geographically, the Strait of Hormuz forms the main route for the seaborne transport of oil, natural gas, and other commercial goods exiting the Persian Gulf and is classified as an international strait for navigation under both regional and international maritime law.

Geographical Location of the Strait of Hormuz - (Anadolu Agency)

Geographical Location

Location and Boundaries of the Strait

Iran lies to the north of the Strait of Hormuz and Oman to the south. The strait extends between Larak Island off the Iranian coast and Greater Qeshm Island belonging to Oman, and it is the only maritime route connecting the Persian Gulf to the Indian Ocean. At its narrowest point, the territorial waters of Iran and Oman meet, and this section of the strait lies entirely within the sovereign territory of the two countries.

Length, Width, and Depth Structure

The length of the Strait of Hormuz is approximately 104 nautical miles. Its width varies from 20.75 nautical miles (about 38 kilometers) at its narrowest point to 52.5 nautical miles (about 97 kilometers) at its widest. The deepest areas are generally located near the Omani coast in the southern section, where depths exceed 650 feet (about 200 meters). Along the route between the eastern and western ends of the strait, there are two-way navigation channels each 3 kilometers wide, with a 3-kilometer buffer zone between them.

Geographical Components

The Iranian coastline to the north of the strait has seen limited settlement due to its hot and arid climatic conditions. The Omani coastline to the south consists of the Musandam Peninsula, characterized by high, rocky mountainous terrain. The Musandam Peninsula, which is part of Oman, occupies a strategic position controlling the entrance to the Strait of Hormuz.

The islands in the vicinity of the strait include:

• Kish Island (formerly Qasem): Iran’s largest island, approximately 115 kilometers long and 18 kilometers wide. It is rich in natural gas, salt, and oil resources.
• Larak Island: Located near the Iranian coast in the eastern part of the strait. It is a central point for maritime traffic.
• Hormuz Island: The strait is named after this island. Located near Bandar Abbas on Iran’s coast, it holds military and strategic importance.
• Hengam Island: Located south of Kish Island and composed of three parts: Old Hengam, New Hengam, and Arab Hengam.
• Abu Musa, Greater Tunb, and Lesser Tunb Islands: Islands subject to sovereignty disputes between Iran and the United Arab Emirates. Iran has maintained a military presence on these islands since the 1970s.

Other small islands in the area include Um el-Ghanem, Farur, Beni Farur, Serri, and Sirri, most of which are under Iranian control. Iran’s naval bases in Bandar Abbas, Bushehr, and Chabahar also enhance its strategic control over the strait.

Hydrographic and Meteorological Characteristics

Sea Depth and Current Characteristics

The Strait of Hormuz is generally deep and well-suited for open-sea navigation. The deepest areas lie just off the Musandam Peninsula, where depths exceed 200 meters. As the strait approaches the Iranian coast, depth decreases, with some sections dropping below 25 meters, making them unsuitable for large tankers. Consequently, commercial vessels largely follow the Traffic Separation Scheme (TSS) established by the International Maritime Organization (IMO).

Currents generally flow east-west and show minimal seasonal variation. Under normal conditions, current speed does not significantly impede maritime traffic.

Visibility and Weather Conditions

Weather conditions in the Strait of Hormuz are predominantly hot and dry for most of the year. The highest temperatures occur in July and August. The region typically experiences low humidity but windy conditions. Near the Omani coast, winds sometimes cause intense dust transport. Along Iran’s southern coast, visibility is significantly reduced due to morning fog and dust haze. This affects navigation, particularly during tanker loading operations.

During dry periods, especially in summer, thin layers of dust and haze formed over the sea by wind can limit the performance of both visual and radar-based navigation systems. In addition, steady coastal winds increase humidity, indirectly affecting terminal operations.

Strategic and Economic Importance

Transit Route for Energy Trade

The Strait of Hormuz is one of the world’s busiest transit points for the transport of crude oil and liquefied natural gas (LNG). In the first ten months of 2023, an average of 20 million barrels of oil passed through the strait daily. This volume represents approximately 30% of global seaborne oil transport. During the same period, LNG transit through the strait totaled 90 billion cubic meters, equivalent to 20% of global LNG trade.

Major Exporting Countries and Routes

Major exporting countries via the strait include Saudi Arabia, Iran, Iraq, Kuwait, United Arab Emirates (UAE), and Qatar. Saudi Arabia, Kuwait, and some UAE export routes bypass the strait. For example, Saudi Arabia’s East-West Pipeline (Petroline), with a capacity of 5 million barrels per day between Abqaiq and Yanbu, transported approximately 1.7 million barrels per day in 2023. Similarly, the UAE’s pipeline from Abu Dhabi to Fujairah Port in Oman has a capacity of 1.5 million barrels per day and operates at 60% utilization.

Iran, however, has no alternative pipeline routes outside the Gulf. Consequently, nearly all of its exports transit through the Strait of Hormuz.

Connection to Asian Markets

In 2022, 82% of crude oil transported through the Strait of Hormuz was destined for Asian markets. Major importers include China, India, Japan, and South Korea. That same year, 25% of LNG shipments to Asia passed through the strait, compared to 13% destined for Europe.

Capacity of Alternative Routes

The total capacity of existing pipeline alternatives to the strait is limited to 4.2 million barrels per day, equivalent to approximately one-quarter of daily oil traffic through the strait. Qatar and the UAE have no alternative routes for LNG exports; all their LNG reaches global markets exclusively through the Strait of Hormuz.

Islands in the Strait and Legal Disputes

Islands Under Sovereignty

Eight major islands lie around the Strait of Hormuz, seven of which are under Iran’s de facto control. Iranian coastal islands such as Kish, Hormuz, Larak, and Hengam are utilized for settlement and military purposes. These islands serve different roles based on their proximity to the coast and water depth. For instance, Larak Island’s central location makes it strategically important for maritime traffic.

Kish Island, the largest of these islands at approximately 115 kilometers in length and 18 kilometers in width, is the largest landmass in the strait’s vicinity. The island, which holds natural gas and salt reserves, is also economically significant.

Disputed Islands

Greater Tunb, Lesser Tunb, and Abu Musa islands are subject to sovereignty disputes between the United Arab Emirates (UAE) and Iran. These islands have been under Iranian control since 1971. The UAE continues to assert its claims, while Iran maintains de facto control.

These three islands hold strategic importance due to their proximity to the entrance of the Strait of Hormuz, enabling both surveillance of maritime traffic and military presence. Iran maintains naval and air bases on these islands to sustain its military presence in the region.

Boundaries Under International Maritime Law

At the narrowest points of the strait, Iranian and Omani territorial waters overlap. This situation was regulated by a joint declaration signed by both countries on 7 March 1974. The declaration affirmed mutual commitment to ensuring the safety of international navigation and freedom of transit through the Strait of Hormuz. On 25 July 1974, Iran and Oman signed an agreement delimiting their continental shelf boundaries.

International Law and Transit Regime

Legal Basis of Transit Rights

The Strait of Hormuz is classified under international maritime law as an “international strait for navigation.” The 1982 United Nations Convention on the Law of the Sea (UNCLOS) provides for a “transit passage” regime for such straits. Transit passage grants continuous, rapid, and unimpeded rights of passage to warships, merchant vessels, submarines, and aircraft.

Articles 37 to 44 of UNCLOS regulate transit passage rights, which limit the sovereignty of coastal states. Under this regime, coastal states cannot suspend or completely block transit. However, passage must be “non-threatening” and “harmless.”

Positions of Iran and Oman

Iran has neither signed nor ratified the 1982 UNCLOS. In its official statement at the time of signing, Iran declared that the transit passage regime applies only to states that are parties to the convention. Iran therefore asserts it is not bound by this regime and permits only “harmless passage.”

Oman signed UNCLOS and ratified it on 17 August 1989. However, Oman has also expressed reservations regarding transit passage. In its declaration at signing, Oman affirmed its recognition of the right of harmless passage but reserved the right to apply its own legal regulations for reasons of peace and security. In particular, it requires prior permission for warships.

Debates on Navigation Regimes

The concepts of transit passage and innocent passage have been controversial since the 1958 Geneva Convention. The 1982 UNCLOS clarified the previously ambiguous concept of “innocent passage” in Article 19. This provision was introduced to restrict coastal states’ arbitrary blocking of passages deemed “harmful.”

Although Iran and Oman recognize UNCLOS to varying degrees, they have not actively interfered with certain transit practices. For example, neither country directly responded to U.S. warships transiting the strait without prior permission in the 1990s.

IMO Traffic Separation Scheme and Practical Applications

Maritime traffic in the Strait of Hormuz is managed through the Traffic Separation Scheme (TSS) established by the International Maritime Organization (IMO). This system creates two-way, 3-kilometer-wide transit lanes with a central safety buffer zone. In the narrowest sections, this traffic regulation lies within Omani territorial waters.

This arrangement is a technical measure designed to reduce congestion, limit collision risks, and enhance navigation safety for civilian vessels. Warships are also expected to comply with these routing schemes, although coastal states’ enforcement authority in this regard is limited.

Historical Background and Military Incidents

Iran-Iraq War Period (1980–1988)

During the Iran-Iraq War, shipping traffic around the Strait of Hormuz was frequently targeted, a period known in literature as the “Tanker War.” Both sides launched attacks on civilian vessels to disrupt each other’s oil exports. 1984 saw a sharp escalation, with over 500 commercial and oil tankers damaged or sunk.

Downing of the Iranian Passenger Aircraft in 1988

On 3 July 1988, the U.S. Navy warship USS Vincennes shot down an Iranian Airbus A300 passenger aircraft over the Strait of Hormuz. All 290 people on board were killed. The United States described the incident as a tragic error due to misidentification, while Iran claimed it was deliberate.

Developments Between 2008 and 2012

In January 2008, Iranian small naval vessels approached three U.S. warships in a threatening manner. In 2010, the Japanese oil tanker M. Star was attacked in the Strait of Hormuz; the attack was claimed by the Abdullah Azzam Brigades, linked to Al-Qaeda.

In January 2012, Iran threatened to close the strait in response to international sanctions over its nuclear program. In May of the same year, the Iranian navy fired on a Singapore-flagged tanker and seized another cargo vessel.

Events of 2019

In 2019, a series of incidents occurred in and around the Strait of Hormuz. In May, four civilian vessels were attacked, including two Saudi Arabian oil tankers. In June, two additional tankers were attacked south of the strait. The United States attributed these attacks to Iran, which denied responsibility. In the same month, Iran shot down a U.S. unmanned aerial vehicle. In July, the U.S. warship USS Boxer claimed it had destroyed an Iranian drone it deemed threatening; Iran denied this claim.

That same month, Iran seized the British-flagged tanker Stena Impero, alleging it had violated maritime regulations. The United Kingdom labeled the incident an “act of piracy.”

2021 and Beyond

In July 2021, an attack was carried out on an oil tanker owned by an Israeli businessman, resulting in the deaths of two crew members, one British and one Romanian. In 2022, 21 million barrels of oil passed daily through the Strait of Hormuz, equivalent to 21% of global liquid fuel consumption.

In 2023, Iranian units seized a container ship allegedly linked to Israel near the Strait of Hormuz. In April 2024, Iran launched direct missile and drone attacks against Israel in retaliation for an attack on its consulate in Damascus; simultaneously, shipping traffic in the strait was closely monitored.

2026 Developments and the Closure of the Strait of Hormuz

On 28 February 2026, following large-scale attacks by the United States and Israel on Iran, security risks in the Strait of Hormuz rapidly increased and maritime traffic significantly declined. According to Iranian state media, the final decision to close the strait was made by the Iranian Supreme National Security Council and requires government approval. After the conflict began, a sharp drop in shipping traffic was observed, with reports based on MarineTraffic data indicating that at least 150 oil and LNG tankers had anchored outside the strait in the Gulf waters. The United Kingdom’s Maritime Trade Operations (UKMTO) announced the presence of “significant military activity” in the region and reported a maritime security incident north of Kumzar in Oman.

According to analysis by energy and maritime data company Kpler, oil shipments through the Strait of Hormuz dropped sharply immediately after the conflict began. On 27 February 2026, a total of 15 tankers carrying 21 million barrels of crude oil and petroleum products transited the strait. On 28 February 2026, 18 tankers transported approximately 21.6 million barrels of oil and petroleum products. However, as security risks escalated rapidly, on 1 March 2026, only three tankers managed to transit the strait, carrying approximately 2.8 million barrels of oil. Thus, compared to the daily average of 19.8 million barrels, there was a drop of approximately 86%.

As hostilities intensified, on 1–2 March 2026, many global shipping companies announced they had suspended transit through the Strait of Hormuz. Maersk declared it had indefinitely halted all vessel transits and rerouted some routes around the Cape of Good Hope. Mediterranean Shipping Company (MSC) temporarily suspended new reservations to the Middle East. During the same period, some container ships were reported to have altered their routes to make a U-turn to avoid the Strait of Hormuz.

On 1 March 2026, Iran confirmed it had targeted a tanker for failing to comply with transit instructions; the Oman Maritime Security Center announced that in an attack on a Palau-flagged tanker in the Musandam waters, four people were injured and the crew was evacuated. Simultaneously, allegations emerged that the Iranian Revolutionary Guard had broadcast via VHF Channel 16 in the Persian Gulf: “No vessel will be permitted to transit.” Although Iranian authorities have not issued an official state decree declaring the strait closed, Iranian media and military sources have asserted that the Strait of Hormuz is effectively closed.

As of 2 March 2026, maritime security risks in the region were reported to have reached a “critical” level. The United Kingdom’s Maritime Trade Organization (UKMTO) confirmed multiple attacks on commercial vessels in the Oman Gulf, around Musandam, and in the territorial waters of the United Arab Emirates and declared that security conditions in the Strait of Hormuz had reached the highest risk level. On the same date, Iranian Revolutionary Guard Corps Deputy Commander Brigadier General Ibrahim Jabbari, in a televised statement, declared: “The Strait of Hormuz is closed. We will attack every vessel attempting to pass.”

As tensions escalated, as of 2 March 2026, 706 non-Iranian oil and product tankers were reported waiting on either side of the Strait of Hormuz. Of these, 334 were carrying crude oil, 109 were carrying dirty petroleum products, and 263 were carrying clean petroleum products; the vessels were anchored at various points in the Persian Gulf, Oman Gulf, and Arabian Sea. Although loading operations continued within the Gulf, the reduction in eastward exits from the strait caused delays in cargo dispatch and extended waiting times.

On 2 March 2026, British-based maritime insurers NorthStandard and London P&I Club, Norwegian firms Gard and Skuld, and the American Club announced the cancellation of war risk insurance coverage for waters around Iran and the Persian Gulf. The notices stated this decision would take effect on 5 March 2026.

As of 3 March 2026, maritime traffic in the Strait of Hormuz was largely halted, with numerous vessels stranded in the region. Global shipping and logistics companies began evaluating emergency operational adjustments, including war risk surcharges, route diversions, and alternative land transport via other ports. Freight rates and insurance costs rose, and supply chains experienced delays.

In response to developments in the region, on 3 March 2026, U.S. President Donald Trump announced that the United States could take new measures to ensure the security of its energy shipments. In a social media post, Trump stated he had directed the U.S. International Development Finance Corporation (DFC) to provide political risk insurance for energy trade passing through the Gulf and added: “If necessary, the U.S. Navy will begin escorting tankers through the Strait of Hormuz.” The U.S. administration indicated it could take additional steps to ensure the free flow of global energy supplies.

Geopolitical Tensions in the Strait of Hormuz

Iran’s Military and Political Approach to the Strait

Iran possesses the capacity to exert control over transit through the strait due to its possession of the northern and northeastern coastal strip and numerous islands. Since the 1970s, it has maintained military presence on various islands, notably Abu Musa, Greater Tunb, and Lesser Tunb. Iran’s naval bases in Bandar Abbas and Bushehr, along with its control over Larak Island, position it to directly influence the northern corridors of the strait.

The Iranian government has periodically halted or seized oil tankers transiting the Strait of Hormuz as a military response to diplomatic tensions. Examples of this approach were evident in 2019 and 2023. Iranian statements regarding transit through the strait assert that vessels within its sovereign waters can be monitored and that any transit deemed threatening may be blocked.

U.S. Maritime Security Policies

The United States has maintained a permanent naval presence in the region to ensure the security of commercial and military vessels transiting the Strait of Hormuz. The U.S. Fifth Fleet, operating from its base in Bahrain, monitors navigation safety around the strait. Since the 1980s, the U.S. Navy has directly intervened in certain transit incidents, particularly during military confrontations in 1988, 2008, and 2019.

The U.S. administration, particularly in relation to Iran’s nuclear program and regional activities, has periodically formed multinational naval task forces to prevent tensions in the strait from disrupting energy markets. Various maritime security initiatives have been undertaken to safeguard international maritime transport.

Approaches of International Actors

Because energy trade through the Strait of Hormuz serves markets in Asia, Europe, and the Americas, many countries view the security of this passage as a priority in their foreign policy. Countries such as the European Union and Japan have engaged in diplomatic and economic efforts to preserve stability in the strait. Major energy importers such as India, China, and South Korea also closely monitor the openness of these sea lanes.

Gulf countries such as Saudi Arabia and the United Arab Emirates have constructed alternative pipeline routes and developed export strategies to redirect shipments away from the Strait of Hormuz to mitigate potential blockade scenarios. Nevertheless, these countries continue diplomatic engagement regarding the maritime transit regime in the region.