More than 1,100 ships have been affected by GPS interference in the Persian Gulf since the start of the war, according to shipping company Windward. Attacks which pose numerous risks to navigation and contribute to the blockage of the strategic Strait of Hormuz, according to experts interviewed.

Published on: 03/05/2026 - 8:03 p.m. Modified on: 03/06/2026 - 2:31 p.m.

It is a key crossing point for world trade that is almost at a standstill. Since the outbreak of conflict in the Middle East, several hundred ships have dropped anchor on either side of the Strait of Hormuz which separates Iran from the Arabian Peninsula.

The Iranian Revolutionary Guards, who declared on Wednesday March 4 that they had “total control” of the strait, had warned as early as February 28 - the first day of Israeli-American strikes on Iran - that no boats were allowed to cross it, then threatened to target those who ventured there. Since then, several ships have been attacked, notably by drones, and maritime security agencies have raised the security risk in this strait through which 20% of the world's oil passes to “critical” level.

But these physical threats are not the only challenge these boats face. They also face increased electronic interference.

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More than 1,100 vessels affected

On March 1, the maritime company Windward reported that more than 1,100 boats had been affected by GPS interference in the Persian Gulf in 24 hours.

These interferences are not entirely new to the region. “Incidents have been reported intermittently since mid-2025, but their scale has increased exponentially following the military escalation of February 28,” explains George Voloshin, independent energy analyst, contacted by the Observers editorial team.

There are two major forms of GNSS interference - the acronym GNSS refers to global positioning satellite systems, including the American GPS system.

The first, and simplest, is GNSS jamming. “Jamming saturates radio signals sent by satellites with powerful ‘noise’ on the same frequency,” explains George Voloshin. “The receiver then loses connection with the satellites.”

More sophisticated, GNSS spoofing (or “spoofing”) consists of “introducing false information into the GNSS receiver” so that it “produces false navigation data”, deciphers Thomas Withington, electronic warfare expert at the Royal United Services Institute.

These practices have become increasingly common in conflict zones: Russia, for example, uses them to protect its infrastructure against Ukrainian drones. But this interference also affects the various electronic devices of nearby civilians, as well as planes or boats. Most ship navigation systems rely on GPS data. This is particularly the case for AIS, which allows their traceability.

Ships appearing inland

Windward thus identified, between February 28 and March 2, 35 areas in which ships saw their signals falsified or displaced.

The company also identified numerous vessels positioned incorrectly, including a “dozen boats” appearing inland, around the Emirati airport of Al Hamra.

Other boats were found to be located at a nearby nuclear power plant, while “hundreds of ships” appear to follow perfect circular trajectories off the coast of the Emirates, Qatar or Oman – signs, again, of navigation interference.

“When GPS lies, ships stop”

The day after the start of the conflict, the Joint Maritime Information Center (JMIC), led by a multinational naval coalition, warned that this interference was acting as a “risk amplifier”.

The risks linked to interference can indeed be severe, underlines George Voloshin:

“[Jamming] results in a complete loss of positioning data, erratic movements on digital charts. [...] As for spoofing, it can make a vessel believe it is in safe waters when in reality it is drifting towards land or into the territorial waters of a hostile state. This can lead to catastrophic accidents, such as groundings or collisions, in narrow shipping channels.”

This interference thus constitutes a “significant factor” in the “de facto” blocking of the Strait of Hormuz, according to Todd Humphreys, expert in GNSS interference and researcher at the University of Texas at Austin. “Tankers must move very slowly if they only have radar and visual cues to avoid collisions,” he explains to our editorial staff.

“When GPS lies, ships stop,” global data and analysis provider Kpler also wrote on March 1 in response to confirmation of the presence of interference in the area. “Ships cannot rely on their position, so many choose not to leave at all.”

According to Kpler, tanker traffic in the strait is down about 90% compared to last week.

“Psychological and operational barrier”

But why such electronic interference and who is causing it?

It is impossible to determine with certainty their source. Several experts interviewed, however, consider Tehran's involvement likely, such as Todd Humphreys:

"The GPS [interference] received by maritime traffic in the Strait of Hormuz is almost certainly the work of Iran. AIS data from vessels in the vicinity of the Strait of Hormuz clearly indicates the presence of spoofing [spoofing of GPS, Editor's note] and not simple jamming. It is evident that this GPS spoofing is designed to affect surface vessels and appears to be concentrated in the vicinity of the Strait. All of this suggests an intention to paralyze traffic in the area, an action for which only Iran has a motive.”

In June 2025, during the Twelve Day War between Israel and Iran, 900 boats in the Strait of Hormuz and the Persian Gulf had already been affected by interference, as reported by Bloomberg. The JMIC then indicated that the interference was coming from the Iranian port city of Bandar Abbas.

George Voloshin also suggests that the Iranian route is favored. He emphasizes:

"By making the strait electronically impassable, Tehran can stop a flow of 21 million barrels of oil per day and cripple global LNG markets, while maintaining a degree of deniability. Jamming offers a more invisible and pervasive form of control than the physical threat of drones, although the two are used in concert. It creates a psychological and operational barrier that deters ships from attempting any crossing. [...] This tactic also protects coastal installations Iranian weapons against Western satellite-guided munitions, since jamming degrades the accuracy of GPS-based missiles and drones.”

But the expert still specifies that “the very nature of electronic warfare often makes it possible to plausibly deny any involvement.” “Other regional actors may also deploy jamming systems for their own defensive needs, making it difficult to identify a single source,” he explains.

“Most participants carry out GNSS attacks in one form or another”

For Dimitris Ampatzidis, analyst at Kpler, this interference is primarily the work of actors “seeking to protect their territory”:

"It could be Iran as well as the military bases in Abu Dhabi, Dubai or Doha. This does not mean that they are targeting ships. They are simply trying to jam GPS tracking systems to avoid being hit. The maritime sector is not their main target; what we are seeing in maritime transport is only a collateral effect."

The analyst explains having identified several areas affected by this interference: three in Iran, but also two in the United Arab Emirates, one in Qatar and one in the center of the Gulf of Oman.

Questioned by the editorial staff of Observers, the account

The account studied interference patterns observed between the UAE and the Strait of Hormuz and concluded that they “appeared to be attributable to certain Israeli, US and NATO systems.”

For Thomas Withington also, different actors could be at the origin of the interference:

"The Iranians are most likely looking to protect potential targets. The same goes for the United States and other countries in the region. I think most of the participants are carrying out GNSS attacks in one form or another. Because otherwise, you simply have no way to protect yourself electronically against a GNSS threat."

Concerning the interference affecting maritime traffic in the Strait of Hormuz, however, he explains:

"The Gulf States, the United States, and Israel all have an interest in keeping maritime traffic flowing through the Strait of Hormuz. I imagine that the use of jamming by the United States and its allies will be orchestrated to minimize interference with civil shipping as much as possible, although proximity will inevitably cause some disruption. Conversely, Iran has a vested interest in using jamming as a lever to disrupt civil shipping in the Persian Gulf; they are probably being much less scrupulous with their jamming techniques. I think the US and its allies use GNSS jamming primarily for defensive purposes, while the Iranians use it more offensively.”

Air traffic affected

This electronic interference is not limited to the Strait of Hormuz alone. They have also been identified over the Arabian Peninsula, particularly with consequences on air flights.

Co-founder of SkAI Data Services, a Swiss company which developed a map listing the interference detected by air flights, Benoît Figuet saw this interference appear as early as February 28. Although many airspaces have been closed, part of the low remaining traffic has been redirected south of the Emirates, via Oman or Saudi Arabia. “We realized that a large part of these planes were affected by GPS interference,” he explains.

On March 2, according to data from SkAI Data Services, at least 169 planes flying over the east of the peninsula were, for example, affected by spoofing.

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