President Donald Trump’s decision to reimpose a maritime blockade on Iran’s ports opens a new phase in the confrontation between Washington and Tehran and places the Strait of Hormuz again at the center of a crisis with consequences that go beyond direct military clashes. The move aims to prevent maritime trade with the Islamic Republic, increase economic pressure on the Iranian government and, according to the White House, protect one of the world’s most important energy routes.
The United States Central Command (CENTCOM) announced that its naval forces will resume a naval blockade targeting vessels entering or leaving Iranian ports—an operation that was previously carried out from April 13 to June 18 and was suspended after a ceasefire agreement between the parties.
Although described as a “naval blockade,” the measure does not mean a physical closure of the Strait of Hormuz nor a total halt to commercial navigation in the Persian Gulf. Its purpose is narrower: to prevent commercial ships from trading with Iran through a US Navy-managed system of surveillance, interception and diversion of vessels.
In practice, any ship whose origin or destination is an Iranian port can be identified, intercepted and ordered to change course. If the ship’s master complies, the vessel continues; if not, the United States warns it may immobilize the ship using military operations.
At the same time, Washington says other commercial traffic will continue to receive protection while transiting the region’s waters, and it has asked all mariners to maintain contact with US naval forces when approaching the Gulf of Oman and the approaches to the Strait of Hormuz.
The distinction between blocking Iranian ports and closing the Strait of Hormuz is crucial to understanding the measure’s reach. Hormuz remains an international maritime corridor open to ships from various countries. However, nearly all of Iran’s major Persian Gulf ports rely on that passage to access international trade, so controlling access to those terminals exerts significant pressure on Iran’s economy without fully halting global navigation.
The reimposition of the maritime blockade follows President Trump’s declaration that the June memorandum of understanding was void because Iran allegedly continued attacking merchant ships near the Strait of Hormuz despite agreeing to reduce hostilities. The move also coincides with an escalation of US military operations.
Over the weekend, US forces reported striking roughly 140 Iranian military targets using fighter aircraft, drones and warships. CENTCOM also confirmed the first operational use of maritime drones to destroy a submarine and vessel maintenance facility in Bandar Abbas, Iran’s main military port and a strategic site on the Strait of Hormuz.
Tehran responded with tougher rhetoric. Army spokesman Brig. Gen. Mohamad Akraminia said the armed forces “will not yield an inch” on the Strait of Hormuz and asserted that the passage “will never be reopened by war, aggression or US attacks.” The Islamic Revolutionary Guard Corps reiterated that the strait’s closure will remain in effect while US intervention continues and warned that any attempt to change that situation will be met with a military response.
At the same time, Iran has intensified attacks on vessels operating near the Strait of Hormuz and has launched missiles and drones against US bases and countries allied with Washington, including Bahrain, Qatar, Kuwait, the United Arab Emirates, Jordan and Oman, broadening the conflict’s regional impact.
The new US offensive also revives tactics used during the blockade’s first phase. Between April and June, CENTCOM said it diverted more than 140 vessels that complied with orders, disabled nine ships that breached the blockade and allowed passage for over 50 commercial vessels carrying humanitarian aid.
Beyond its military dimension, the reestablished naval blockade has a strong economic component. Shipping companies that continue to deal with Iran will face a higher risk of interception, and maritime insurance and shipping costs could rise if tensions escalate further.
The strategic importance of the Strait of Hormuz explains market concerns. Before the outbreak of hostilities, about one-fifth of the world’s traded oil passed through that corridor daily. Although the United States insists that international navigation will remain open for ships not trading with Iran, any military incident in the area can disrupt energy supply chains and put upward pressure on global oil prices.
Adding uncertainty, President Trump announced that the United States will begin charging a fee equal to 20% of the cargo’s value to vessels seeking US protection to cross the Strait of Hormuz. If implemented, the proposal would not only raise maritime trade costs but also reinforce the role Washington seeks as guarantor of security for one of the world’s most strategic sea lanes—a role Iran rejects and that risks prolonging the confrontation in the Persian Gulf.