Hormuz Reopens After MoU Signing: Chinese-Led First Movers Alongside Sanctioned Iran Tonnage

At a Glance

• The U.S.-Iran memorandum of understanding (MoU) was signed on June 17, and June 18 marked the first day of commercial reopening at the Strait of Hormuz.
• 18 transits were recorded across the June 17 to 18 window, the highest single-window count of the conflict.
• The first wave of commercial movers is predominantly Chinese-affiliated, with five of seven documented first movers Chinese-linked, alongside European, Japanese, and Saudi tonnage among the early departures.
• Three Saudi-flagged supertankers carrying approximately six million barrels of crude transited the Strait dark in the hours following the signing.
• Iran’s oil export network began reconstituting ahead of the signing, with three NITC vessels ending months-long dark periods at Chabahar on June 16 and six more sanctioned tankers transiting the Strait of Malacca westbound toward Iran.
• More than 80 IRGC high-speed craft were observed moving in an unusual, undirected pattern through the Kharg Island waiting area, a behavior not previously recorded at this location.
• The CMA CGM SAN ANTONIO remains stationary mid-Strait, held since being boarded and looted by IRGCN small craft in late May.

Operational Overview

The Strait of Hormuz is reopening. Following the June 17 signing of the U.S.-Iran memorandum of understanding, the first commercial vessels stranded inside the Arabian Gulf since the war began transited the corridor on June 18. The June 17 to 18 window recorded 18 transits, the highest single-window count of the conflict.

The first wave is predominantly Chinese-affiliated, with European, Japanese, and Saudi tonnage also among the early departures. The pattern of confidence is broadening beyond the highest-risk appetite shipowners. The lead-up to the signing showed a clear anticipatory pattern across both commercial and sanctioned traffic.

Iran’s oil export network has been reconstituting in parallel, and at pace. National Iranian Tanker Company vessels ended months-long dark periods at Chabahar, sanctioned tankers departed long-running anchorages off the Strait of Malacca, and additional sanctioned vessels are now approaching the Strait of Hormuz and the Bab al-Mandeb. A zombie vessel and an IRISL-affiliated cargo vessel transited outbound in the same 24-hour window as the legitimate first movers.

Windward assesses that the June 18 picture is one of cautious momentum rather than full normalization. Legitimate commercial traffic, sanctioned vessels, and unresolved military activity are moving simultaneously through the same corridor.

The Lead-Up to the Signing

In the days before the signing, commercial shipping began repositioning for a reopening rather than transiting through it. By June 15, 14 transits were recorded in a single day, the highest count of the month, but the volume reflected a cautious uptick rather than a surge. The June 16 to 17 window recorded a slight dip back to 12 transits, with movement still calibrated to the formal signing rather than to the agreement-in-principle. Vessels began sailing to positions closer to the Strait and waiting at anchor, many with AIS switched off. 

At least 23 VLCCs were tracked converging on UAE ports from as far as the South China Sea, and EO imagery over Khor Fakkan on June 17 detected 128 vessels at the anchorage, with at least 45 dark ballast tankers showing signs of pre-departure preparation. The overall pattern was beginning to resemble a pre-war baseline.

Iran’s oil export network did not wait. Three National Iranian Tanker Company vessels reactivated their AIS at Chabahar on June 16 and departed the holding area without interdiction. 

At least five U.S.-sanctioned Iran-trading tankers departed long-running anchorages off the Riau Archipelago in the Strait of Malacca, sailing westbound toward Iran after months of immobilization under the U.S. blockade. 

Five potential blockade breakers were assessed near the Strait on June 16, all exhibiting active sanctions evasion behavior, and one sanctioned Iran-linked tanker was observed transiting the uncleared Traffic Separation Scheme, the primary shipping lane that has not been swept of mines since the conflict began.

Across the same window, IRGC small-craft activity remained active in the central Strait, with approximately 25 to 30 high-speed craft documented across the June 16 collection windows. A sanctioned Iran-flagged chemical tanker was observed deviating from typical transit lanes east of Hormuz under suspected IRGCN fast-boat escort. Eleven dark tankers were holding across the Kuh Mubarak and Bandar-e Jask offshore anchorages, with a VLCC observed at the Kuh Mubarak single-point mooring for the first time. Kharg Island’s two crude terminals were empty for the sixth consecutive day, and the bulk carrier at the LPG and Sulphur terminal had passed its estimated departure window without leaving the berth.

By the eve of the signing, three threads were already in motion: cautious commercial preparation, Iran’s sanctioned fleet reactivating, and sustained IRGC and staging activity across the corridor.

The First Wave of Movers

On the morning of June 18, the first wave of commercial vessels stranded in the Middle East Gulf since the war began moved to transit the Strait of Hormuz. The initial movers were predominantly Chinese-affiliated. Of the seven vessels tracked transiting in the morning window, five were Chinese-linked. The cohort included a Hong Kong-flagged MR tanker owned by the Chinese government-controlled COSCO, a Hong Kong-flagged supramax bulk carrier, a Panama-flagged bulk carrier with Chinese owners and crew, and a China-flagged Panamax bulk carrier. The first movers had been stranded inside the Arabian Gulf for 109 to 128 days since the war began.

European-flagged tonnage was also among the early departures. A France-flagged LNG carrier transited outbound, with particular diplomatic significance given that French President Emmanuel Macron was present alongside President Trump at the MoU signing on June 17. The vessel performed a small loop near the Strait entrance, assessed as a course adjustment to avoid a nearby Iran-flagged cargo vessel, before proceeding outbound. An Italy-flagged vehicle carrier was also among the early movers.

Three Saudi-flagged supertankers carrying approximately six million barrels of crude oil transited the Strait in the hours following the signing, representing the largest single departure through the corridor in weeks. Two had been dark since April 17 and 18, respectively. A third may not yet have reactivated its AIS. All three transited with AIS off.

A Japanese-controlled VLCC was observed transiting the northern corridor, a notable move given that Japanese-affiliated owners had been among those expected to wait for greater assurance before committing to transit. 

A concentration of Iran-flagged fishing vessels was also noted near the outbound entrance to the Strait in the same window.

Legitimate and Sanctioned Traffic in the Same Window

The June 17 to 18 window recorded 18 transits through the Strait of Hormuz, the highest single-window count of the conflict. The inbound group totaled eight vessels, seven AIS-transmitting and one dark. The outbound group totaled ten, all AIS-transmitting.

Among the inbound vessels was an Iran-flagged tanker operated by the National Iranian Tanker Company transiting via the northern corridor with AIS off, consistent with documented NITC concealment practice ahead of Arabian Gulf port calls. The vessel carries multiple overlapping OFAC designations, including SDN, IRN, and SECON. A Botswana-flagged inbound tanker with a fraudulent registry and dual Iran and Russia General sanctions designations had previously been observed operating between UAE Barakah and Iraq Khor Al Zubair with multiple Hormuz transits since April. A Sri Lanka-flagged cargo vessel inbound via the southern corridor was logged as departing Al Mutrah Military Port in Muscat, an Omani military facility not typically used for commercial departures, with no commercial explanation identified.

The outbound group comprised four tankers, five cargo vessels, and one barge, all using the northern corridor. Four of the first movers stranded inside the Arabian Gulf since the war’s opening phase were among the outbound transits. Two previously assessed potential blockade breakers were confirmed to transit outbound in this window. A Cook Islands-flagged tanker operating at 98.3% capacity with Iranian-origin cargo, dark from June 12 to 16 while advancing toward the Strait, transited via the northern corridor. A Malta-flagged cargo vessel that completed an approximately 13-day port call at Imam Khomeini concurrent with the Cook Islands tanker, and that had experienced GPS jamming and Null Island coordinate spoofing following its June 10 Strait transit, also transited outbound. Both vessels share Marshall Islands corporate services addresses across their ownership structures.

The most significant outbound transit was a Panama-flagged tanker classified as a zombie vessel, with no verified owner, operator, or valid registry. Its movement alongside an outbound IRISL-affiliated cargo vessel indicates that Iran has no intention of establishing transparent or compliant shipping practices, even with a sanctions waiver expected to take effect for its oil and petrochemicals.

Iran’s Parallel Restart Comes Into Focus

The fuller picture of Iran’s restart, partially visible in the days before the signing, came into sharper focus on June 18.

At Chabahar, three National Iranian Tanker Company vessels ended blockade-era dark periods on June 16. DIONA (IMO 9569695), an Iran-flagged VLCC, ended a 94-day dark period. HERO 2 (IMO 9362073), an Iran-flagged Suezmax, ended an 81-day dark period. SONIA 1 (IMO 9357365), an Iran-flagged VLCC, also ended an 81-day dark period. The three-vessel coordinated AIS reactivation constitutes an advance restart of sanctioned Iranian crude export capacity ahead of any waiver taking effect.

In the Strait of Malacca, six U.S.-sanctioned Iran-trading tankers departed anchorages off the Riau Archipelago, where they had been stranded since the U.S. imposed the blockade on Iranian ports in mid-April. The group comprises one VLCC, three LPG carriers, and two Suezmax tankers, all now transiting westbound toward Iran via the Indian Ocean.

Three additional sanctioned vessels are assessed as approaching the Strait of Hormuz. The group includes a 176-meter oil products tanker with a fraudulent Botswana flag and dual Iran and Russia General sanctions designations, a 333-meter crude oil tanker with a fraudulent Guyana flag sanctioned under Iran programs and recording six flag changes, and a 239-meter tanker with a fraudulent Guinea flag that has been holding at Fujairah anchorage since April in a posture consistent with awaiting the MoU outcome.

Two further sanctioned vessels are approaching via the Bab al-Mandeb. The first is a 330-meter Netherlands Caribbean-flagged tanker with seven flag changes, routing westbound through the Red Sea under Iran sanctions. The second is a 247-meter Equatorial Guinea-flagged tanker with 11 flag changes, the highest in the current cluster, sanctioned under both DPRK and Russia General programs, and completing a complex multi-leg route from Russia through China before now returning westbound.

Empty Terminals and an Unusual IRGC Pattern at Kharg Island

EO imagery collected over Kharg Island on June 18 presented a significantly changed picture from prior collections. All three of the island’s loading facilities, comprising the eastern terminal, the western terminal, and the LPG and Sulphur terminal, were empty. The sulphur-loading bulk carrier first observed at the LPG and Sulphur terminal on June 10 had departed within the approximately 72-hour window between the June 15 and June 18 collections.

Approximately 21 dark tankers remained in the eastern waiting area, all assessed as laden based on visible freeboard. The count is consistent with the 21 to 24-vessel range observed throughout June.

The most notable finding was the detection of more than 80 IRGC high-speed craft moving throughout the waiting area in an unusual, non-directed pattern, weaving between the stationary tankers with no clear heading, no convoy formation, and no consistent speed. This kind of high-density undirected small-craft activity in the waiting area has not been observed in prior Kharg Island collections. Possible explanations include logistics runs between vessels, a patrol surge, or coordination between the waiting fleet and the Iranian naval element. No hostile action or boardings were visible.

Three work barges were observed just south of the island, each accompanied by a tug or service vessel, alongside at least four additional tugs and a separate service vessel. Windward assesses that with all loading terminals currently idle and the offshore waiting tankers laden, Iran may be using this window to conduct terminal maintenance ahead of resuming loading operations.

Staging Clusters and Mid-Strait Holdouts

SAR imagery collected over the eastern Hormuz approach on June 18 at 02:06 UTC identified a cluster of approximately 23 vessels, with only three transmitting AIS. The cluster’s location and size are consistent with prior collections at this staging area, where vessels gather before transiting inbound, likely to resupply or queue for transit. The pattern is established and recurring rather than a one-time event.

Three vessels were assessed as stationary within the Strait itself. The CMA CGM SAN ANTONIO, a container ship boarded and looted by more than 73 IRGCN small craft in late May and early June, has not moved since that incident and was confirmed present at its previously identified mid-Strait position. An LPG tanker was stationary with AIS active and no wake visible. A third vessel, a large dark tanker, was stationary with a small vessel alongside, assessed as possibly receiving a supply or crew transfer.

At least five dark contacts were assessed as moving inbound along the western corridor in sequence, consistent with a northbound track into the Arabian Gulf rather than clustering behavior. All five were operating dark.

Outlook

The Strait of Hormuz is reopening, but the picture on June 18 is not one of normalization. Legitimate commercial first movers, sanctioned vessels reconstituting at pace, and unresolved military activity are all moving through the same corridor.

The Traffic Separation Scheme remains uncleared, with no minesweeping operations yet underway. The CMA CGM SAN ANTONIO remains stationary mid-Strait. More than 80 IRGC high-speed craft were observed moving unusually through the Kharg Island waiting area. And the transit of a zombie vessel and an IRISL-affiliated cargo vessel in the first 24 hours after the signing indicates that Iran’s oil export network does not intend to operate within international shipping norms, even with a sanctions waiver expected to take effect.

The operational risk environment is transitioning, but it has not normalized. The full picture of any post-conflict Strait will take weeks, not days, to settle.