Maritime GNSS Interference Worldwide: A Cumulative Analysis 2025

Over the past few years, dozens of separate reports, advisories, and news articles have documented GNSS interference incidents affecting maritime navigation. However, these materials remain scattered across different organizations, agencies, and media outlets — each offering only a fragment of the global picture. To understand the broader scale and dynamics of this phenomenon, we conducted a cumulative analysis of all publicly available information, aggregating and normalizing data from multiple sources to identify worldwide trends.
This study does not claim to represent a complete or definitive dataset; it is based solely on open publications and verifiable reports. Nevertheless, even this partial view reveals a dramatic surge in both the number of interference incidents and the vessels affected — demonstrating that maritime GNSS disruption has evolved from isolated regional cases into a global operational challenge.

This article does not claim scientific precision or statistical completeness. The cumulative trends presented here should be interpreted as indicative rather than absolute. The observed growth in reported GNSS interference incidents may reflect both an actual increase in occurrences and the growing awareness and attention from media outlets, maritime authorities, and regulatory organizations. At the same time, we are confident that only a small fraction of real interference events ever reach the public domain. The true scale of maritime GNSS disruption is likely far greater than what is visible through open-source reporting.

• Over 10,000 vessels were officially reported affected by GNSS interference in Q2 2025 — an eightfold increase compared to the previous quarter.
• Rise in regulatory and media attention highlights how GNSS interference has moved from a niche concern to a recognized systemic risk for global maritime operations.
• The maritime industry is already behind in its response, with mitigation measures still fragmented and largely reactive.

This analysis is based entirely on open-source information. We systematically reviewed and quantified all publicly available reports, advisories, and media publications referring to GNSS interference incidents affecting maritime navigation between 2021 and 2025.

Each record was verified by cross-checking multiple sources, normalized by region (Black Sea, Baltic Sea, Eastern Mediterranean, Red Sea, Persian Gulf/Strait of Hormuz), and deduplicated to avoid counting the same event multiple times.

Only sources that included quantitative data — such as the number of incidents, vessels affected, or clear time references — were included in the cumulative dataset. Narrative reports without numerical evidence were used solely to confirm regional presence and trends.

Primary Open Sources Reviewed

• NDU Press – “PNT as a Weapon System” and related analyses describing GPS spoofing activity in the Black Sea region.
• U.S. Maritime Administration (MARAD) – Advisory 2021-003, reporting possible GPS spoofing in the Persian Gulf.
• BBC / Reuters – Coverage of Russian GNSS jamming in the Black Sea following the invasion of Ukraine, with supporting data referenced by NDU Press.
• Defense News – Reports describing the onset of GNSS jamming in the Baltic region linked to the war in Ukraine.
• Lloyd’s List – Multiple maritime security reports covering sustained GNSS spoofing in the Black Sea, regional NATO Shipping Centre briefings, and subsequent disruptions across the Eastern Mediterranean and Red Sea.
• Reuters – Articles on Baltic GNSS interference affecting both aviation and maritime navigation, and continued disturbances reported by Nordic authorities and coast guards.
• Lloyd’s List (April 2024) – Detailed accounts of large-scale spoofing incidents, including 117 vessels simultaneously displaced to Beirut Airport and later 227 ships spoofed across the Eastern Mediterranean.
• NATO Shipping Centre / Lloyd’s List (mid-2024) – Updates on GNSS interference observed during the Sudan conflict and related Red Sea disruptions.
• Associated Press (AP) – Summary of Latvian authorities logging over 820 jamming incidents by mid-2025, attributed to sustained Russian activity.
• Reuters / Nordic authorities – Warnings of a significant rise in persistent Baltic jamming through early 2025.
• UKMTO (United Kingdom Maritime Trade Operations) – Advisories on localized GNSS interference near Port Sudan and Bab al-Mandab in August 2025.
• Windward: Key maritime disruptions in Q2 of 2025
• Spire: GNSS interference report: Russia 2024/2025 – Part 1 of 4: Kaliningrad & the Baltic Sea
  Spire: GNSS interference report: Russia – Part 2 of 4: Crimea and the Black Sea Region
  Spire: GNSS interference report: Russia – Part 4 of 4: Black Sea & Romanian airspace

Analytical Approach

Each data point was normalized by time and region to enable consistent comparison across sources. When multiple outlets covered the same event, the earliest and most data-rich report was treated as the primary reference, while others were marked as corroborating.

The dataset therefore represents a documented minimum — a conservative lower bound of the real scale of maritime GNSS interference.

Despite its open-source nature and inherent incompleteness, this cumulative analysis provides the clearest quantitative picture yet of how GNSS interference has evolved from regional anomalies into a global maritime phenomenon.

GNSS interference has grown from a regional concern into a global maritime risk. In 2021, only a few vessels were reportedly affected by spoofing activity in the Black Sea near Crimea (NDU Press). By 2022–2023, jamming and spoofing incidents had spread into the Baltic region, with dozens of events confirmed by national authorities and media, including over 26 documented cases in Latvia during 2022 (AP) and sustained jamming in 2023 (Reuters).
In the Eastern Mediterranean, spoofing reached an unprecedented scale in April 2024, when 117 ships simultaneously appeared at Beirut Airport due to falsified GNSS signals (Lloyd’s List). The Red Sea and the Gulf of Aden were also affected in 2024–2025 amid conflict in Sudan and renewed instability in Yemen (NATO Shipping Centre, Reuters).

The most dramatic escalation came in June 2025, when Windward AI reported over 3,000 disrupted vessels in the Persian Gulf and Strait of Hormuz within less than two weeks.

The first graph shows the number of publicly reported incidents of GNSS interference by region between 2021 and 2025. In this context, an “incident” refers to a documented episode — a single report or case describing GNSS jamming, spoofing, or anomalous signal activity. Each incident may represent an isolated event affecting one vessel or a prolonged disruption influencing hundreds.

The count of incidents therefore reflects reporting activity, not necessarily operational scale. It demonstrates a steep increase in public attention to the issue, driven by the growing involvement of maritime organizations, insurance firms, and news agencies that now regularly document GNSS-related anomalies.

This growth in the number of recorded incidents illustrates not only more frequent disruptions but also a rising institutional and media engagement with the subject of maritime GNSS interference.

The second graph summarizes the estimated number of vessels directly or indirectly affected by GNSS interference, based on reports that included quantitative data.

This dataset consolidates quantitative information from documented GNSS interference events — for example, 117 vessels spoofed near Beirut (April 2024), 227 ships simultaneously affected in the Eastern Mediterranean (Lloyd’s List, April 2024), and nearly 3,000 vessels disrupted during the June 2025 global spike (Windward AI).

Only reports that explicitly stated the number of vessels affected were included. However, such sources remain scarce — many publications describe interference events qualitatively, without indicating how many ships were involved. As a result, no direct data points exist for Q3 and Q4 2024. For these periods, approximate values were extrapolated based on the reported region, duration of interference, and estimated maritime traffic density.

The data reveal a dramatic surge in Q2 2025, when both regional and multi-regional interference incidents reached an unprecedented scale.

1. Growth in Reporting Activity
The number of documented GNSS interference reports and issuing organizations has increased by more than 250% compared to last year.
This rise reflects both a higher frequency of interference and stronger institutional engagement — as maritime authorities, regulators, and global media now treat GNSS disruption as a standard risk factor in navigation and safety assessments.

2. Five Major Regions Affected
Interference has expanded from two regional hotspots — the Black Sea and the Baltic — to at least five key maritime areas: the Eastern Mediterranean, the Red Sea, the Persian Gulf, the Black Sea, and the Baltic Sea. GNSS disruption now spans all main commercial shipping corridors, confirming its transition from a local issue to a global operational challenge.

3. 10,000+ Ships Disrupted in Q2 2025
In the second quarter of 2025, more than 10,000 vessels were officially reported affected by GNSS interference — an eightfold increase compared with the previous quarter. This surge indicates both a real escalation in jamming and spoofing activity and an improvement in reporting systems across the maritime domain.

The data show a pattern that can no longer be ignored. GNSS interference is spreading faster than the industry’s ability to adapt, creating a widening gap between technological dependence and real operational resilience. Modern ships rely on satellite navigation for every stage of their voyage — from open-sea routing to precise maneuvering in ports. As interference becomes more frequent and intense, even small positional errors can escalate into serious navigational failures, especially in congested waterways such as the Baltic or the Strait of Hormuz.

Despite years of warnings, the maritime sector remains largely reactive. Onboard detection systems, redundant positioning methods, and coordinated incident reporting are still the exception, not the rule. The 2025 collision between two tankers in the Strait of Hormuz — preceded by recorded GNSS and AIS anomalies — served as a clear warning of what lies ahead.

Unless decisive action is taken, the combination of unreliable signals, human error, and institutional inertia will eventually converge. When it does, the question for the industry will not be if a major incident occurs, but when.

The problem of protecting ships from GNSS interference is not something that can be solved with one device or one quick fix.
It’s a complex challenge that requires combining different technologies and approaches — from navigation methods and antenna systems to smarter onboard software. There’s no silver bullet here, only a combination of tools that together can make ships more resilient.

1. The first step is awareness
The most important thing right now is that crews must know in real time when their vessel is in an interference zone.
Just like weather or collision alerts, captains and officers need a clear signal on the bridge when GNSS signals are being jammed or spoofed — and an indication of how serious the threat is.
Without that awareness, even experienced navigators can make mistakes, especially in narrow or crowded waterways.

2. System of defense
To stay safe, navigation must become multi-layered again — using not just GNSS, but also radar, inertial systems, and even traditional visual navigation where possible. The idea is simple: if one layer fails, the others still keep the ship moving safely.

3. What we’re doing about it
At GPSPATRON, we’ve created a marine version of our interference detection algorithms, designed specifically for use on ships.
They can detect and classify GNSS interference directly on board, showing the crew exactly when and where it’s happening.
Right now, we’re taking this a step further — developing risk models that can estimate how a particular type of interference might affect the ship’s navigation systems.  In simple terms, we want the system not just to say “there is interference”, but also “this type of interference could disrupt your GNSS receiver in this way.”

The truth is, the maritime industry is already running behind this problem. The time to act was five years ago. But it’s not too late to start building protection now — through awareness, collaboration, and technology that helps crews make the right decisions at the right time. If you’d like to learn more about how to protect your vessel or discuss practical ways to add interference detection on board, get in touch with us.