The US military has begun blocking shipping traffic at Iranian ports, a move that would prevent an estimated two million barrels a day of Iranian oil from entering world markets, further exacerbating global supply shortages.
Here you will find details about the blockage and its implications for oil markets.
What has been announced?
Following the no-deal conclusion of peace talks in Islamabad between U.S. and Iranian negotiators over the weekend, President Donald Trump declared that the U.S. Navy will “initiate the process of BLOCKADING all ships attempting to enter or exit the Strait of Hormuz.”
U.S. Central Command stated Monday that unauthorized vessels entering or leaving the blocked zone will face “interception, diversion and seizure.” He added that US forces would not impede the freedom of navigation of ships transiting the Strait of Hormuz bound for non-Iranian ports.
The Iranian Revolutionary Guard responded to Trump by warning that the approach of military ships to the strait would be considered a violation of the ceasefire and would be acted upon severely and forcefully.
What implications does this have for the flow of oil?
Blocking Iranian shipments would disconnect an important source of oil from world markets. Iran exported 1.84 million barrels per day (bpd) of crude in March and has exported 1.71 million bpd so far in April, compared with an average of 1.68 million bpd in 2025, according to Kpler data.
However, the surge in Iranian production before the start of the war on February 28 has led to near-record levels of Iranian oil loaded onto ships, with more than 180 million barrels in transit or in floating storage earlier this month, according to Kpler data. Of that amount, approximately 100 million barrels were in the waters of Malaysia, Indonesia and China.
Flow of oil from other Gulf producers?
Maritime traffic through Hormuz, severely restricted by the Iranian blockade since the start of the war, remains virtually paralyzed despite the two-week ceasefire agreement between Washington and Tehran, announced on April 7.
On Tuesday, a Chinese tanker carrying methanol loaded in Hamriyah, United Arab Emirates, crossed the strait in what appeared to be the first tanker transit since the start of the US blockade. Two other ships also crossed the strait.
On Sunday, before the blockade began, two Pakistani-flagged oil tankers, the Shalamar and the Khairpur, entered the Gulf to load goods from the United Arab Emirates and Kuwait. A third ship, the Liberian-flagged supertanker Mombasa B, also transited the strait on Sunday and was weighing down in the Gulf.
The Maltese-flagged VLCC Agios Fanourios I, which attempted to pass through the strait on Sunday to load Iraqi crude oil bound for Vietnam, turned around and became anchored near the Gulf of Oman.
According to Kpler, as of April 7, some 187 tankers loaded with 172 million barrels of crude oil and refined products were in the Gulf.
The most affected importers
Before the war, most of Iran’s oil exports were sent to China, the world’s top crude importer. Last month, the United States announced a sanctions waiver that has allowed other buyers, including India, to import Iranian oil.
According to ship tracking data from LSEG and Kpler, India was scheduled to receive its first shipment of crude oil from Iran in seven years this week.
Before the war, about 20% of global oil and natural gas exports were transported through the Strait of Hormuz, with most shipments headed to Asia, the main importing region.
