A growing number of commercial vessels are crossing the Strait of Hormuz with their tracking systems switched off, as shipowners seek to avoid risks posed by the escalating conflict between the United States and Iran, Bloomberg reported.
According to preliminary data from ship-tracking firm Kpler analyzed by Bloomberg News, all six commodity carriers that transited the strategic waterway on Sunday did so with their transponders turned off. So-called “dark crossings” have outnumbered observable passages over the past several days.
Ship-tracking data based on Automatic Identification System (AIS) signals showed no vessels passing through the strait early on Monday. However, ships have continued to appear on opposite sides of the waterway—either in the Persian Gulf or the Gulf of Oman—after previously broadcasting their positions from the other side, indicating they crossed the strait without transmitting their location, Bloomberg reported.
Shipowners opt for ‘dark crossings’
The news outlet said shipping companies are increasingly choosing to switch off their transponders while navigating the Strait of Hormuz as Washington and Tehran exchange missile and drone attacks and issue competing claims over who controls the strategic waterway.
According to the outlet, observable traffic through the US-backed southern shipping corridor along Oman’s coast has effectively stopped, with the last publicly tracked transit via that route taking place on Wednesday.
By contrast, the northern route designated by Iran continued to record a limited number of crossings through Saturday.
Attacks reshape shipping routes
The decline in traffic through the southern corridor follows a series of Iranian attacks on vessels using the Omani route, including ships that had disabled their transponders, Bloomberg reported. The attacks appear to have discouraged commercial traffic from using that passage.
Shipowners now face a difficult choice: use the northern route under Iranian oversight and risk additional costs or possible US penalties, or attempt riskier alternatives amid heightened military tensions.
Dark transits began months ago
According to Bloomberg, secret crossings through the Strait of Hormuz first became widespread in mid-April, when the United Arab Emirates began transporting oil on tankers operating without active transponders.
That strategy helped reduce the impact of oil supply disruptions during the early stages of the conflict, preventing shortages from becoming as severe as initially feared, the report said.
US and Iran issue competing claims
The report noted that Tehran and Washington continue to offer conflicting accounts over the status of the waterway.
Iran has said vessels must obtain permission from an Iranian authority before transiting the Strait of Hormuz, while US Central Command maintains that ships can still navigate the waterway through open international shipping lanes.
Iranian attacks continue
According to Bloomberg, Iranian forces have attacked four vessels over the past seven days, with all incidents occurring near the northeastern side of Oman’s Musandam Peninsula—an area associated with the US-supported southern transit corridor.
The Islamic Revolutionary Guard Corps (IRGC) said on Sunday it intercepted two vessels that it claimed were endangering maritime traffic by travelling along what it described as an “illegal route.”
