Big Changes in the Strait of Hormuz Over the Weekend! More than 20 Ships Passed Through on Saturday, Dropped to Zero on Sunday?

The Strait of Hormuz saw a dramatic reversal over one weekend—on Saturday, the number of passing ships surged to nearly a seven-week high, but plummeted on Sunday. This upheaval reflects the sharp escalation of US-Iran tensions ahead of the ceasefire agreement deadline.

According to media citing the shipping data analytics company Kpler, more than 20 vessels successfully passed through the Strait of Hormuz on Saturday, marking the highest daily record since March 1. Yet just one day later, the situation abruptly worsened. CCTV, citing US vessel tracking data, reported that as of the afternoon of the 19th (Sunday) UK time, there were no observed vessel transit records through the Strait of Hormuz that day. Xinhua, citing a report released by the UK-based maritime analytics company Windward on the 19th, said that after Iran briefly reopened the Strait of Hormuz, it closed it again, and in the past 36 hours, 35 vessels turned back en route out of the Strait.

The previous day, as the US-Iran ceasefire agreement deadline (Tuesday evening) approached, confrontations landed one after another: US forces forcibly seized an Iranian cargo ship in the Gulf of Oman for the first time; Iran announced renewed restrictions on commercial shipping in the Strait of Hormuz, characterizing it as direct retaliation for the US’s continued maritime blockade. According to Xinhua, at least 13 oil tankers on the 18th abandoned attempts to leave the Persian Gulf midway, giving up passage through the strait.

The Strait of Hormuz is one of the world’s most important energy transportation corridors. Any substantial restriction on its shipping freedom would have a direct impact on global oil and gas supplies and energy prices. Transit numbers plunged from a monthly high to zero in 48 hours, underscoring the high uncertainty this route faces.

Saturday Transit Reaches Monthly High, Cargo Sources Diverse

According to Kpler data, among the more than 20 vessels that passed the Strait of Hormuz on Saturday, cargo sources included Gulf oil-producing countries such as Saudi Arabia, UAE, Qatar, and Bahrain, with cargos including crude oil, LPG, naphtha, refined oil products, and fertilizers.

Specifically, Liberian-flagged VLCC Fpmc C Lord loaded about two million barrels of Saudi crude destined for Mailiao, Taiwan; Liberian-flagged tanker Navig8 Macallister carrying about half a million barrels of UAE naphtha bound for Ulsan, Korea; Indian-flagged tanker Desh Garima carrying about 780,000 barrels of UAE Das crude bound for Sri Lanka. Additionally, Panamanian-flagged tanker Crave loaded UAE LPG bound for Indonesia; bulk carrier Merry M transported Saudi petroleum coke to Ravenna, Italy.

Xinhua, citing UK-based maritime analytics company Windward on the 19th, said Iran briefly reopened then closed the Strait of Hormuz again, and in the past 36 hours, 35 vessels turned back en route out of the strait. The report says Iranian ships reacted cautiously after Iran announced reopening the strait on the 17th. On the 18th, passage through the strait was initially sparse but then rapidly increased, as vessels rushed to transit ahead of worsening circumstances. A total of 35 vessels passed the strait that day: 8 entered—including 4 tankers, 2 bulk carriers, 2 other cargo ships; 27 exited—including 8 tankers, 3 bulk carriers, 15 other cargo ships, 1 passenger vessel.

The report says after Iran announced the closure again on the 18th, Windward confirmed 13 ships turned back, including 4 container ships that had already passed the strait and then reversed. The same day saw three ship attack incidents, bringing the total attacked since the outbreak of US-Israeli-Iranian conflict to 29 vessels. These attacks further accelerated vessels turning back.

Ships have continued attempts to break through the US blockade on Iranian ports. Windward assessed that between the 17th and 19th, 20 vessels likely broke through the US blockade.

US Deploys Force for the First Time, Seizes Iranian Cargo Ship

The direct backdrop for plummeting transit volume on Sunday was the head-on US-Iran clash over the weekend.

Xinhua, citing a statement by Trump on social media, reported that the US Navy missile destroyer "Spruance" used force against an Iranian cargo ship named "TOUSKA" in the Gulf of Oman, blowing a hole in the engine room to force it to stop. Trump claimed the US Marine Corps now controls the 274-meter cargo ship, which is sanctioned by the US Treasury.

This is the first time the US has seized an Iranian vessel by force in the Gulf of Oman, marking a shift of US blockade actions in the Strait of Hormuz from deterrence to actual enforcement, pushing bilateral conflict to a new dangerous stage.

Iran offered a starkly different account. Xinhua, citing Iran's Mehr News Agency, reported that on the 19th US forces opened fire on an Iranian merchant vessel, trying to force it to return to Iranian waters, but Iran’s Islamic Revolutionary Guard Navy quickly arrived to assist, causing the US military to withdraw. The report did not disclose the merchant vessel’s name.

Iran Tightens Shipping Control, Revolutionary Guard Leads Pressure

As military friction escalated, Iran simultaneously tightened shipping control in the Strait of Hormuz. According to media reports, a senior adviser to Iran’s Islamic Revolutionary Guard stated the Guard decided to sharply restrict commercial shipping through the strait again this weekend, clearly characterizing it as direct retaliation against the Trump administration’s continued blockade of Iranian vessels.

The adviser added that the Revolutionary Guard is not opposed in principle to resumed dialogue, but its core demand is for Iran to have stronger bargaining chips at the negotiating table—which is precisely the strategic rationale for tightening strait control on the eve of the ceasefire deadline.

Ceasefire Deadline Approaches, Negotiations Uncertain

The US-Iran two-week ceasefire agreement will expire this Tuesday evening, and serious doubts remain about whether new talks can be launched on schedule.

Xinhua and CCTV reported that a US delegation has arrived in Islamabad, Pakistan’s capital, believed to be groundwork for new US-Iran negotiations. US Vice President Vance also plans to lead a team to Pakistan this week to advance talks.

However, Iranian state media categorically denied the claim of "second round negotiations" and emphasized that as long as the US maintains its maritime blockade, Iran will refuse to return to the negotiating table.

The number of crossings through the Strait of Hormuz plunged from a monthly high to zero in 48 hours, vividly displaying the vulnerability of this crucial channel. As the ceasefire deadline draws near and both sides apply extreme pressure for negotiating leverage, short-term transit prospects for the strait remain highly uncertain, and energy markets will stay intensely sensitive to related developments.

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