Neither Open nor Closed: How “Dark” Crossings Turned the Strait of Hormuz into a Permanent Gray Zone

The transponder workaround is keeping oil moving and the war alive — sparing the global economy just enough to remove every deadline for peace

One hundred thirty-six days into the U.S./Iran war, the world’s most important oil chokepoint has settled into something stranger than a blockade. Only six ships crossed the Strait of Hormuz on Sunday — the lowest count in five weeks — and every one of them ran silent, with its Automatic Identification System switched off. Dark transits have now outnumbered observable ones for three straight days, and by Windward’s count roughly 40% of all traffic in the strait is running without AIS. Spoofing, which had faded in late June, resumed on July 9.

The numbers trace the whole arc of the crisis. IMF PortWatch counted roughly 80 transit calls a day through the strait in January and February, a waterway moving about 20 million barrels of oil daily — one-fifth of world consumption. After the war began on Feb. 28 and Iran declared the strait closed on March 2, traffic collapsed to near zero within days and Brent spiked as high as $126. An April ceasefire produced a brief tolled reopening — Iran charged more than $1 million per ship — before the strait shut again on April 18. The June 17 memorandum of understanding lifted traffic back toward 50 transits a day by late June. Then the shooting resumed: Kpler counted 30 crossings on July 8, 22 on July 9, and just six by Sunday, after Iranian forces struck four vessels in seven days off Oman’s Musandam peninsula — all on the U.S.-backed southern corridor, which has since gone completely quiet. What still moves hugs Iran’s designated northern lane or moves dark.

STRAIT OF HORMUZ CRISIS TRACKER

As of Monday, July 13, 2026

Daily vessel transit calls through the Strait of Hormuz with 7-day average, January 1 – July 5, 2026. Source: IMF PortWatch daily chokepoint transit calls; event dates from press reporting.

A dark transit is not lawless improvisation; it is an organized military-commercial workaround. Masters silence their AIS broadcast but report positions every two hours to British and American naval coordination cells, keep navigation lights burning as maritime law requires, hand-steer through the narrows, and drill crews on radar-only navigation. The real gatekeeper is now the insurance market: war-risk premiums have reached 2 to 6 percent of hull value per transit — as much as $6 million to push a single $100 million tanker through — a de facto toll only the highest-margin cargoes can clear.

This is why Brent sits near $83 rather than $126. Markets have priced a partial-flow equilibrium — “skirmish, calm, transit, repeat,” as one analyst put it — reinforced by Saudi and Emirati pipelines routing some crude around the strait, reserve releases, and softening demand. But the manageable oil price is precisely the problem. An outright closure would force a resolution: either the U.S. Navy reopens the strait or the global economy compels a settlement. The dark-transit workaround relieves that pressure on both capitals at once. Iran demonstrates leverage without the total closure that would exhaust Chinese patience; Washington demonstrates the strait is “not closed” without having to fight it fully open. The risk is privatized onto mariners and underwriters, and every successful silent crossing extends the war’s political shelf life. That is the forever-war mechanism: adaptation without resolution.

The externalities will outlast the conflict. AIS is safety infrastructure — the collision-avoidance commons of the world’s busiest oil lane — and normalizing dark and spoofed transits erodes it while blurring the line between legitimate shippers and the sanctioned “dark fleet” that pioneered these tactics. Note, too, what Iran’s targeting implies: last week’s four ships were chosen by route, not transponder status, meaning silence protects crews less than shippers hope. From here, watch whether war-risk underwriters withdraw cover altogether (a harder stop than any blockade), whether Iran begins hunting dark ships directly, and the PortWatch seven-day average — the cleanest single line between an uneasy new normal and genuine strangulation of one-fifth of the world’s oil.

Meanwhile, President Donald Trump and Iran traded competing claims Monday over control of the Strait of Hormuz, with Trump ordering the U.S. naval blockade of Iran restored and Tehran insisting Washington has no authority to manage the strategic waterway.

Trump said the strait is open and would remain open “with or without Iran.” He said the renewed blockade would prevent Iranian ships — and vessels serving Iranian customers — from entering or leaving Iranian ports while allowing ships bound for other countries to continue using the strait. U.S. Central Command said enforcement will begin Tuesday, July 14, at 4 p.m. ET and warned that vessels violating the blockade could be intercepted, diverted or seized. Humanitarian cargoes will be permitted following inspection.

Trump also declared that the U.S. would become the “guardian” of the Strait of Hormuz and proposed charging 20% on cargo shipped through the waterway to reimburse Washington for providing security. The administration has not explained how the fee would be calculated or collected, and the International Maritime Organization said international straits should remain free of tolls and that there is no legal basis for mandatory transit charges.

In a Fox News interview Monday, Trump blamed Iran for destroying last month’s interim agreement, saying Tehran had broken another completed deal and warning that the U.S. would continue hitting Iran “very hard.” The comments followed additional U.S. strikes on Iranian naval, radar and coastal facilities and Iranian attacks against U.S. and allied installations across the Gulf region.

Iran rejected Trump’s assertion of U.S. control. Iran’s top joint military command said Washington had no role in deciding the strait’s future and would not be allowed to intervene. Foreign Minister Abbas Araghchi responded sarcastically to Trump’s proposed fee, saying Iran had always been the strait’s guardian and would remain so “forever,” while suggesting Tehran would charge less than Trump’s proposed 20%.

Iran’s Revolutionary Guards said normal shipping could return only after U.S. military intervention in the waterway ends. Foreign Ministry spokesman Esmaeil Baghaei described the June memorandum of understanding as being “in crisis” and said Iran would not comply with its obligations if Washington failed to honor its commitments, although he said talks through Oman, Qatar and Pakistan were continuing.

Trump separately announced that he will deliver a televised address to the nation Thursday, July 16, at 9 p.m. ET. He did not disclose the subject, but the announcement came hours after the blockade and transit-fee declarations, making Iran and the Strait of Hormuz the likely central focus. The immediate test will arrive before the speech, when U.S. forces begin enforcing the blockade Tuesday afternoon and Iran decides whether to challenge it directly.