How will Trump’s blockade of Iranian oil work?
After US-Iran peace talks failed in Pakistan over the weekend, US President Donald Trump said the US Navy would intercept ships entering or leaving any Iranian port or coastal facility through the Strait of Hormuz.
By the time the war broke out in late February, a fifth of the world’s maritime oil trade passed through the Strait of Hormuz, the narrow stretch of water between the Persian Gulf and the Indian Ocean.
If successful, the blockade would cut off Iran’s main source of revenue by halting its roughly 2 million barrel-a-day oil export trade, which Trump is betting will force Tehran back to the negotiating table.
US officials said the goal was to strip Iran of gains from control over the waterway, which Tehran effectively closed when the war began, stranding hundreds of oil and gas tankers.
According to reports, Trump designed the blockade to prevent Tehran from charging up to $2 million (€1.71 million) per ship for safe passage through the strait.
“Anyone who pays illegal tolls will be denied safe passage on the high seas,” Trump wrote on Truth Social on Sunday. He also said that the US Navy would also “begin destroying mines laid in the strait by the Iranians”.
US Central Command (CENTCOM), which directs Washington’s military forces, said the blockade would not affect ships sailing to and from non-Iranian ports such as Saudi Arabia, Qatar and the United Arab Emirates.
How will the US Navy enforce the blockade?
The operation, which was scheduled to begin on Monday, was announced with a notice to sailors.
CENTCOM said the blockade “will be implemented in the Gulf of Oman and the Arabian Sea east of the Strait of Hormuz” and will include “the entire Iranian coastline… not limited to ports and oil terminals.”
The advisory continued: “Any vessel entering or departing the blocked area without permission is subject to interception, diversion and capture.”
Maritime law experts said enforcement would rely on standard naval procedures known as the right to visit and search, where US warships stop and inspect tankers and divert them if they are suspected of carrying Iranian oil.
While the use of search and search has precedent in naval warfare, many experts warn that a blockade risks entering disputed territory under the law of the sea, affecting neutral ships and causing long-term disruption in an important international strait.
Within hours of Trump’s announcement, tanker traffic in the strait came to a halt again, according to maritime data company Lloyd’s List Intelligence.
How quickly could the blockade affect Iran’s oil exports?
The US blockade could sharply reduce the ability to load and ship crude from Iran’s main export terminal, Kharg Island in the Persian Gulf, which handles more than 90% of the country’s oil shipments.
Iran continues to export oil despite international sanctions tied to its nuclear program, relying on a shadow fleet of aging tankers, ship-to-ship transfers from Malaysia and other evasion tactics.
The US also gave Iran temporary permission to sell its oil as a measure to help stabilize markets during the ongoing conflict.
The new naval blockade is set to make those loadings more risky and less likely, as operators face the possibility of boarding, diversion or seizure.
Iran’s oil exports last year were worth about $45 billion, or 13% of gross domestic product, according to London-based Capital Economics. With no land pipelines to divert crude oil supplies, Iran has few other non-maritime export options. Even its Jask export terminal on the Gulf of Oman may still be explored by the US Navy.
Continued US pressure could force Tehran to quickly return to the negotiating table as it stands to lose this revenue.
Could the blockade lead to widespread conflict?
Trump’s blockade threat was met with threats of retaliation by Iran’s Revolutionary Guard Corps.
It declared that if Iranian ports faced sanctions, “no port in the Gulf and the Sea of Oman will be safe,” raising fears of an attack on energy or shipping infrastructure among Gulf neighbors.
Ebrahim Rezaei, spokesman for the Iranian parliament’s National Security Commission, also warned that Tehran was ready to respond militarily if necessary.
“This will make the current situation [Trump] It’s more complicated and makes the market – which he’s angry about – more turbulent,” Rezai wrote on X. “And we may also reveal other cards we haven’t used in the game.”
Many American experts have questioned Trump’s move, saying that he may be attracting America towards an open military commitment.
“Trump wants a quick solution. The reality is that this mission is difficult to execute alone and could be unsustainable in the medium to long term,” Dana Stroll, a former senior Pentagon official during the Biden administration, told Reuters news agency.
Neil Shearing, group chief economist at Capital Economics, wrote that the blockade “could also be designed to pressure Beijing to take a more active role in mediating a ceasefire and reopening full trade flows through the strait.”
After Iran, China stands to lose the most from the blockade, as it has bought 80-90% of Iran’s seaborne crude oil exports in recent years.
Shearing also wondered whether the US Navy would seize Allied ships paying tolls to Tehran or Chinese ships in the strait, saying either would represent a “significant escalation”.
Edited by: Tim Rooks