The United States has strengthened its operational position in the Strait of Hormuz, helping restore a substantial share of oil shipments through the strategic waterway. However, Iran retains the geographical advantage and the ability to threaten commercial vessels, leaving control of one of the world’s most important energy routes contested.
The shift follows a US military operation that established a shipping corridor through the southern part of the strait along Oman’s coast. US officials told Axios in August that between 15 and 20 tankers were entering or leaving the waterway each night through the corridor, moving close to 10 million barrels of oil daily at the time.
One US official involved in the operation said American forces had controlled the southern lane for two months, adding that Iran’s Islamic Revolutionary Guard Corps could still disrupt shipping but did not control the entire strait.
The operation has strengthened Washington’s ability to facilitate commercial movement through the waterway, although claims of control need to be distinguished from legal ownership and the ability to guarantee safe passage across the entire route.
Oil flows show a changing balance
Recent shipping data provides further evidence that oil movements have recovered despite the conflict. Kpler estimated that flows through the Strait of Hormuz reached approximately 13.19 million barrels per day in the week ending September 27, compared with a pre-war baseline of about 17.13 million barrels per day.
That represents roughly 77 percent of the previous flow level. The recovery suggests that Iran’s ability to make the waterway commercially unusable has weakened, even though shipments have yet to return fully to normal.
The figures do not mean the United States controls 77 percent of the vessels or the strait itself. They measure the volume of oil moving through the route. Vessel traffic remains disrupted, with some ships using alternative routes, switching off their automatic identification systems (AIS), conducting ship-to-ship transfers or relying on military escorts. Saudi Arabia and the United Arab Emirates have also used alternative pipeline infrastructure to move some crude without sending it through Hormuz.
The difference matters because oil volumes can recover faster than ordinary shipping traffic. A smaller number of tankers carrying large cargoes can move substantial quantities of crude, while other shipowners remain reluctant to enter the area because of security risks.
Iran retains the geographical advantage
Despite the US operational gains, Iran’s position along the northern side of the strait gives it a persistent ability to threaten shipping.
The waterway separates Iran from Oman and measures about 39 kilometres at its narrowest point. Its location makes it a critical passage between the Persian Gulf and the Gulf of Oman, connecting major oil-producing states to international markets.
Iran’s coastline, islands, military installations, surveillance systems, missiles, drones, naval mines and fast attack boats give it several ways to threaten vessels or disrupt navigation. It does not necessarily need to stop every tanker to influence the market. Even the risk of an attack can prompt shipping companies to delay voyages, insurers to raise premiums and operators to seek alternative routes.
The US Navy, meanwhile, has a substantial military presence in the region, with the Fifth Fleet headquartered in Bahrain. Its warships, aircraft and surveillance capabilities provide Washington with the means to escort vessels, monitor maritime activity and challenge attempts to restrict commercial navigation.
The two countries therefore possess different forms of leverage: Iran benefits from proximity to the waterway, while the United States has greater capacity to organise and protect shipping movements through a military-backed corridor.
Iran’s earlier control of shipping has weakened
Iran exercised greater practical influence over the limited traffic moving through Hormuz earlier in the conflict.
In March, shipping reports described an Iranian-controlled clearance system under which vessels were reportedly required to submit identifying and cargo information, obtain approval and use designated routes. Some ships were also reported to have received Iranian escorts or faced demands for payment.
The European Union subsequently said Iran’s Islamic Revolutionary Guard Corps Navy had assumed control of the strait and introduced procedures requiring vessels to provide information about their identities, cargoes and destinations.
That situation has since changed as US forces expanded operations to facilitate traffic through the southern corridor. The shift does not eliminate Iran’s ability to interfere with shipping, but it has reduced Tehran’s influence over a growing share of the oil moving through the waterway.
The US blockade has hit Iranian oil exports
The balance of power is also reflected in the difference between the movement of Gulf oil generally and the movement of Iranian crude specifically.
The United States has used its naval blockade to restrict Iran’s oil trade. Reuters reported that Iranian crude loadings fell from around 2 million barrels per day in March to approximately 220,000–255,000 barrels per day in August.
The restriction has allowed Washington to exert pressure on Iran’s export revenues while helping facilitate the movement of non-Iranian oil through the southern corridor. As a result, overall oil flows can recover even while Iranian shipments remain severely constrained.
This is a significant distinction. The ability to keep much of the region’s oil moving while limiting Iran’s own exports gives the United States substantial operational and economic leverage. It does not, however, mean Washington has eliminated Iran’s capacity to threaten the route.
Neither country owns the strait
The question of control also has a legal dimension. The Strait of Hormuz is bordered by Iran and Oman, but neither country owns the entire waterway as private property, and the United States has no territorial claim to it.
The United Nations Convention on the Law of the Sea provides for transit passage through international straits, requiring that passage not be impeded. However, the legal debate surrounding Hormuz is complicated because neither Iran nor the United States has ratified the convention, and Tehran disputes aspects of how its transit-passage provisions apply.
The existence of coastal-state jurisdiction does not, by itself, give either Iran or Oman an unrestricted right to prevent international navigation. At the same time, international law does not remove the practical security risks created by military conflict or attacks on vessels.
Iran still has leverage over the reopening
Tehran continues to assert that it can determine the conditions under which normal navigation resumes. On October 4, Iranian Parliament Speaker Mohammad Baqer Qalibaf said the strait would not reopen until the United States met seven Iranian conditions linked to a June memorandum of understanding.
The statement underscores that Iran retains enough capacity to threaten maritime security to make the waterway part of its negotiations with Washington. Even with more oil moving through the US-backed southern corridor, the prospect of renewed attacks or further restrictions remains a concern for shipowners and energy markets.
Any serious disruption in Hormuz can affect global crude supply, freight rates, insurance costs and oil prices, with potential consequences for fuel prices paid by consumers.
The balance is therefore divided: the United States has strengthened its operational role in moving and protecting commercial oil shipments, while Iran retains the geographical position and military tools to disrupt them. Washington may currently have the upper hand in facilitating much of the traffic, but neither side can guarantee lasting security without a wider political settlement.