Surge in GPS interference around Strait of Hormuz increases shipping risks

Shipping through the Strait of Hormuz has almost completely stopped. Since the outbreak of conflict in the Middle East, hundreds of vessels have dropped anchor on either side of this strategic passage between Iran and the Arabian Peninsula.

Iran’s Islamic Revolutionary Guard Corps (IRGC) said on Wednesday, March 4, that they had “complete control” of the Strait. From the onset of the US-Israeli strikes on Iran, they had warned that transit through the waterway was not allowed, threatening to target any ship trying to pass. 

Since then, several vessels have come under fire, including from drone strikes. Maritime security agencies raised the threat level to “critical” for the Strait, a key artery which carries 20% of the world’s oil.

Physical threats are not the only challenge these vessels face, however. They must also navigate a surge in electronic interference.

More than 1,100 ships affected

Maritime company Windward said on March 1 that more than 1,100 vessels had been hit by GPS interference in the Persian Gulf within 24 hours.

Electronic interference is not totally new to the region. “Incidents have been reported intermittently since mid-2025, but the scope has increased exponentially in the last 72 hours following the February 28 military escalation,” George Voloshin, an independent energy analyst, told our team.

There are two major forms of interference with Global Navigation Satellite Systems (GNSS) – the umbrella term for technologies like the American GPS.

The first, and simplest, is GNSS jamming. “Jamming disrupts navigation by overwhelming the extremely weak radio signals sent by satellites with high-powered ‘noise’ on the same frequency,” Voloshin explains. “This causes the receiver to lose its lock on the satellites.”

A more sophisticated tactic, GNSS spoofing, works by “introducing false information into the GNSS receiver” in order “to ensure that the GNSS receiver produces false navigation data”, Thomas Withington, an expert in electronic warfare at the Royal United Services Institute in London, told our team.

Such tactics have become increasingly common in conflict zones; Russia, for instance, employs them to shield its infrastructure from Ukrainian drones. However, this interference also affects civilian devices, aircraft, and ships. Most vessel navigation systems – including the Automatic Identification System (AIS) used for tracking – depend on GPS data for positioning and timing. 

Vessels shown to be on land

Between February 28 and March 2, Windward identified 35 distinct jamming clusters in which vessel signals were distorted or displaced. Such clusters have been reported across the UAE, Qatari, Omani, and Iranian waters.

They also found a number of vessels being falsely positioned, including “a dozen ships” shown to be on land, around Al Hamra airport in the United Arab Emirates. 

The signals of other vessels have been diverted to an Emirati nuclear power plant, while “hundreds of other vessels” were shown to create circle-like patterns off UAE, Qatari, and Omani waters – further evidence of electronic interference.

‘When GPS lies, ships stop moving’

In the immediate aftermath of the conflict’s outbreak, the Joint Maritime Information Centre (JMIC), run by Western navies, warned that the GNSS interference was acting as “a risk amplifier”.

And the risks associated with GPS interference are severe, Voloshin told our team:

“[Jamming] results in a total loss of positioning data, erratic movements on digital charts. (...) Furthermore, spoofing can trick a ship into believing it is in safe water when it is actually drifting toward land or into the territorial waters of a hostile state. A captain facing interference risks losing situational awareness, which can lead to catastrophic accidents such as groundings or collisions in narrow shipping lanes.”

Such disruptions thus constitute a “significant factor” in the de facto blockade of the Strait of Hormuz, said Todd Humphreys, an expert in GNSS interferences at the University of Texas in Austin. “Large tanker ships have to move very slowly if they only have radar and visual cues for collision avoidance,” he told our team.

“When GPS lies, ships stop moving,” Kpler, a global real-time data and analytics provider, wrote after electronic interferences were confirmed in the Gulf. “Ships can’t trust where they are, so many are choosing not to go at all.”

Kpler said on March 4 that tanker transits through the Strait of Hormuz were around 90% lower than the preceding week.

‘Psychological and operational barrier’

But why is this electronic interference occurring, and where is it coming from?

While it’s impossible to identify the source of interference, several experts interviewed believe Tehran’s involvement is probable. 

Humphreys said: 

“The spoofing and jamming of GPS signals received by maritime traffic in the Strait of Hormuz is almost certainly Iran's doing. Ships' AIS data near the Strait of Hormuz clearly indicate that GPS spoofing is present, not merely jamming. And it's clear the spoofing is directed to affect surface ships. And the spoofing appears to be concentrated near the Strait. All this suggests an intent to snarl traffic through the Strait, for which only Iran has a motive.”

In June 2025, during the 12-day war between Israel and Iran, more than 900 ships in the Strait of Hormuz and the Persian Gulf had their navigation signals jammed, as reported by Bloomberg. At the time, JMIC said it had received reports of electronic interference stemming from the Iranian port of Bandar Abbas.

Voloshin also points to Iran as a likely source of the interference:

“By making the Strait digitally impassable, Tehran can stop the flow of 21 million barrels of oil per day and paralyse global LNG markets while maintaining a level of deniability. 

Signal jamming provides a more invisible and pervasive form of control compared to the physical threat of drones, though both are used in a coordinated "area denial" strategy. It creates a psychological and operational barrier that prevents ships from even attempting the transit. (...)

This tactic also protects Iranian coastal assets from satellite-guided Western munitions, as the jamming degrades the accuracy of incoming GPS-reliant missiles and drones."

But he also says that “due to the nature of electronic warfare, there is often an element of plausible deniability, as other regional actors may also be deploying jamming systems for their own defensive purposes, further complicating the task of pinpointing a single source”.

‘I would suspect most of the participants are doing GNSS attacks in some shape or form’

For Dimitris Ampatzidis, a risk and compliance analyst at Kpler, these interferences stem primarily from actors “trying to protect their territory”:

“This could be either Iran or the military camps in Abu Dhabi, Dubai and Doha. It doesn't mean that they are targeting the vessels. They are just trying to blend the GPS tracking systems in order to avoid being hit. The core focus is not on the maritime. The outcome that we are seeing on the shipping side is just a side consequence.”

Ampatzidis said Kpler identified several spots affected by such interference: three in Iran, two in the UAE, one in Qatar, and one in the middle of the Gulf of Oman. 

For their part, the people behind the X account @giammaiot2, a group of telecommunications researchers, told our team they believed “the massive increase in GPS jamming and spoofing in the Persian Gulf” was “primarily due to non-Iranian systems, namely Kuwait, Bahrain, Qatar, the UAE, Saudi Arabia, and Oman”.

They analysed the interference configurations observed between the UAE and the Strait of Hormuz and concluded that “they appeared to be attributable to some Israeli, US and NATO systems”.

Withington also said a number of different actors were likely to be behind the GNSS interferences: 

“The Iranians will be very keen to protect potential targets against attack by GNSS-guided weapons and reconnaissance. And equally will the US and the respective countries in the region. I would suspect most of the participants are doing GNSS attacks in some shape or form. Because if you don't, you don't really have a means of protecting yourself electronically from a GNSS threat."

Regarding the disruptions to maritime traffic in the Strait of Hormuz, he said, however:

“The Gulf states, the US and Israel are obviously all quite keen to keep maritime traffic flowing through the Strait of Hormuz. What I imagine is happening is that the use of jamming by the US and its allies in the region will be drafted in such a way to minimise interference to civilian shipping as much as humanly possible, even if there will invariably be some disruption because of proximity.

Whereas Iran will have an interest in using jamming as a means of creating disruption to civilian navigation in the Persian Gulf. They're probably playing much more fast and loose with the jamming in that region.

I think that the US and its allies are primarily using GNSS jamming defensively, whereas the Iranians are using it more offensively."

Air traffic affected

These electronic interferences are not limited to the Gulf and the Strait of Hormuz. They have also been reported across the Arabian Peninsula, affecting regional air traffic.

Benoit Figuet, co-founder of SkAI Data Services, a Swiss company that developed a map tracking flight-detected interference, saw these disruptions emerge as early as February 28. While many airspaces have been closed, some of the minimal traffic remaining was rerouted south of the UAE via Oman and Saudi Arabia. “We noticed that a large portion of these aircraft were being affected by GPS interference,” he told our team.

On March 2, according to data from SkAI Data Services, at least 169 planes flying over the eastern part of the peninsula were hit by spoofing.