GPS Jamming in Strait of Hormuz: A New Threat to Global Shipping

The false coordinates started appearing in perfect circles. Dozens of commercial vessels, each broadcasting its location via GPS, suddenly clustered together on navigation screens—some appearing to hover impossibly over land. For maritime analysts watching the Strait of Hormuz, the pattern was immediately recognisable: someone was jamming the GPS signals that keep hundreds of ships from colliding in one of the world's busiest shipping lanes.

Electronic warfare, once confined largely to active combat zones in Ukraine and the Levant, has escalated to a point where commercial shipping's fundamental navigation infrastructure is being systematically disrupted. The technology keeping supertankers apart is, as one expert describes it, about as secure as an unlocked wifi network.

When navigation becomes guesswork

Michelle Wiese Bockmann, senior maritime intelligence analyst at Windward, counted 35 distinct clusters of vessels broadcasting impossible positions when she examined live data from the region. The interference affects Automatic Identification Systems, the technology ships use to track each other's positions and avoid collisions. When a 300-metre tanker carrying hundreds of thousands of tonnes of crude needs several kilometres to alter course, knowing where nearby vessels actually are isn't optional.

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We can't over-estimate the huge danger this places to maritime navigation and safety

What makes this particularly galling for the shipping industry is that the military doesn't share this vulnerability. Armed forces use M-Code GPS, an encrypted and authenticated version of the technology that resists jamming. Commercial vessels, meanwhile, rely on civilian GPS signals that Alan Woodward at the University of Surrey describes as inherently weak.

The risk isn't that a ship's captain can't determine his own position through backup systems—it's that he has no reliable way to know where everyone else is, particularly at night or in poor visibility.

Military tech versus commercial vulnerability

Military analysts strongly suspect Iran of deploying domestically produced jamming equipment, potentially sourced from Russia or China, according to Thomas Withington, associate fellow at the Royal United Services Institute. The US Department of Defense declined to comment on specific capabilities when approached, though analysts suggest American forces may also be jamming to protect bases and vessels from GPS-guided drones and weapons. The National Hydrographic Office Pakistan has issued warnings about the interference.

Researchers at Zephr.xyz used satellite radar data to detect what they say are jamming signatures within Iran itself, though the BBC notes it hasn't independently verified these findings. The same firm previously studied GPS disruption in Ukraine by strapping smartphones to drones, allowing them to triangulate jammer locations through interference patterns. Sean Gorman, Zephr's co-founder, says he was "amazed at the level of jamming and how powerful it is".

A chokepoint already under pressure

The timing could hardly be worse. Global supply chains remain stressed from ongoing Houthi attacks that have diverted shipping away from the Red Sea, forcing vessels on longer routes around Africa. A major incident in the Strait of Hormuz—say, a collision involving laden oil tankers—would immediately impact energy prices and potentially trigger an environmental catastrophe.

The commercial maritime industry finds itself caught in a conflict where it lacks the defences available to military vessels operating in the same waters.

Anti-jamming technology exists but isn't standard equipment. Defence contractor Raytheon produces Landshield, a system about the size of an ice hockey puck that the company says can detect interference and switch frequencies. Alex Rose-Parfitt, engineering director of Raytheon UK, reports "quite an increase in demand" for such products.

Advanced Navigation, an Australian firm, has developed systems using gyroscopes and accelerometers combined with optical star-mapping as GPS alternatives, though co-founder Chris Shaw acknowledges star-based positioning "is just not very accurate" on its own.

The new normal in electronic warfare

Bockmann characterises the current interference as "next-level" compared to the 12-day Israel-Iran conflict in 2024, suggesting either capabilities or willingness to deploy them have intensified. GPS jamming has become routine in Ukraine and has affected aircraft across Europe, including a plane carrying the President of the European Commission. The phenomenon is expanding both geographically and in sophistication.

Ramsey Faragher, director of the Royal Institute for Navigation, predicts the proliferation of jamming will eventually force the adoption of more secure alternatives. He draws a parallel to wifi networks, which evolved from open access points to password-protected systems as security threats became apparent.

The current reliance on unencrypted GPS signals will one day look reckless

For an industry that moves 11 billion tonnes of goods annually and underpins global trade, that realisation may need to arrive faster than anyone planned. The military-civilian technology gap in navigation has transformed from an inconvenience into a genuine commercial risk.

Whether the shipping industry can retrofit protection across thousands of vessels affected by GPS interference before electronic warfare in critical waterways triggers the collision everyone fears will depend partly on how long the current escalation continues—and whether insurers, port authorities and flag states treat GPS jamming and spoofing across civilian domains as the systemic threat it has become.

More articles by Ross Williams