The Strait of Hormuz Is Splitting in Two — and Most Ships Now Travel in the Dark
Ship-tracking data analyzed by Al Jazeera shows that the Strait of Hormuz, once a single maritime corridor, has fractured into competing Iranian and Omani routes. The vast majority of vessel traffic is now traveling dark or on unclassified paths as Washington and Tehran wage an escalating contest for control of the waterway.
US President Donald Trump claimed the US military remains in control of traffic through the strait and suggested the US might seek to take charge of the territory. Trump also claimed Hormuz was open for vessels to pass through. That directly contradicts Iran's insistence that the waterway is closed to ships that do not seek Tehran's approval before transit. The US has a naval blockade in place targeting all Iran-linked ships, while Washington insists commercial carriers use a southern Omani route, further from Iran's shoreline and operating under US Naval protection.
The territorial reality complicates both positions. The strait lies in the maritime territories of both Iran and Oman. Before the war, it was largely considered a single waterway without distinctions between Iranian and Omani routes, with ships using well-established traffic separation schemes mostly along the central part of the strait. Since the war, traffic has been divided into a northern Iranian route and a southern Omani route. The Iranian route hugs Iran's coast near Larak Island and Qeshm Island and feeds directly into Iranian ports and offshore terminals.
The fragmentation has been accompanied by a dramatic increase in vessels obscuring their movements. Maritime intelligence firm Kpler recorded 112 vessels carrying crude oil, liquefied petroleum gas (LPG), and liquefied natural gas (LNG) transiting the strait between August 1 and August 19, 2026. Of those, 21 openly used the Iranian route and only two formally used the Omani route. The remaining 89, more than 80 percent, went along dark or otherwise unclassified routes.
Dark routing happens when a vessel turns off its Automatic Identification System (AIS) transponder — the onboard device that publicly broadcasts a ship's identity, position, and course — or when the AIS data does not fit neatly into Kpler's defined Iranian or Omani corridors. Mohamed Rafik Halitim, a customer success manager for Maritime and Commodities at Kpler, told Al Jazeera that dark routing makes it highly difficult to determine what proportion of vessels may have used the Omani route or to confirm their precise routing from available data.
The broader traffic picture compounds the opacity. Kpler recorded 236 total ships transiting Hormuz in the same August 1–19 period, including oil and gas vessels and others carrying dry cargo and chemicals. Of those 236, 83 openly used the Iranian route. The remainder were either on the Omani route or dark.
The dark-routing phenomenon is not new, but it appears to have intensified. Windward, a maritime intelligence company, reported that on May 8, 521 radio frequency (RF) transmissions were detected across the Hormuz area, of which only 84 were matched to AIS data. That means the overwhelming majority of vessels transmitting RF signals were not broadcasting identifiable AIS positions. Separately, tracking data analyzed by ABC News (Australia) in March 2026 indicated Iranian-linked oil tankers were using AIS spoofing — broadcasting fake location information — to move through the strait. MarineTraffic has identified AIS spoofing as a growing risk in the maritime industry, noting that by masking the true identity and location of vessels, bad actors can evade detection and carry out illicit operations, with specific reference to Hormuz and the Bab el-Mandeb.
Vessel traffic through the strait has proven resilient to political shocks. According to Argus Media, based on AIS tracking data, traffic through Hormuz did not change after the announcement of a US-Iran peace deal in June 2026. That static traffic picture, set against the surge in dark routing, suggests that whatever the diplomatic temperature, commercial operators are adapting to a sustained environment of risk and ambiguity rather than responding to discrete political milestones.
The geopolitical stakes have widened beyond Iran. Trump threatened to bomb Oman, a US ally, in an apparent bid to dissuade Muscat from striking any deal with Tehran to jointly manage the strait. Oman has historically played a mediating role between the two adversaries. The warning to Muscat narrows the diplomatic space for any negotiated transit framework that does not pass through Washington.
The broader context here is that the data describes a waterway where declarative claims of control, from both Washington and Tehran, collide with a maritime reality in which over four-fifths of oil and gas traffic operates in a surveillance gray zone. The split into Iranian and Omani corridors was a wartime adaptation; the persistence of dark routing well after a declared peace deal suggests it has become a structural feature rather than a temporary measure. With Iran-linked tankers employing AIS spoofing and the majority of RF-transmitting vessels unmatched to AIS data, the picture for anyone trying to verify which route a given ship took, and under whose authority, is increasingly opaque. For energy markets, insurers, and naval planners tracking compliance with US sanctions (government-imposed economic penalties that restrict trade with a targeted country) and Iranian transit rules, the actionable intelligence layer is thinning precisely as the political rhetoric thickens.
