About Shadowfleet.watch
Shadowfleet.watch is an independent shadow fleet tracking website at shadowfleet.watch. Its live map and recorded observations help readers explore the movements of sanctions-listed vessels.
The service matches AIS observations to a vessel watch list, records selected patterns and makes those observations available for inspection. It does not issue sanctions designations or determine whether an activity is unlawful. Its scope includes multiple sanctions programmes rather than only Russian vessels.
For a definition of the term and the wider context, read What is the shadow fleet? This page documents the tracker’s own methods and limits.
Where the data comes from
- AIS positions. AIS broadcasts can include position, speed and identity. This site receives observations through AIS reception and the AISHub exchange network. This is reception-dependent coverage, with gaps and delays, rather than a continuous position fix for every vessel. See the IMO’s AIS overview.
- Sanctions lists. The watch list is built from official registers (US OFAC, EU, UK, Ukraine, Switzerland, Canada, UN) consolidated in the OpenSanctions maritime collection and refreshed daily. Vessels are matched by their IMO number, which stays the same through every name and flag change.
- Reference data. About 3,800 ports from the World Port Index, submarine telecom cables from TeleGeography, Baltic pipelines from EMODnet and curated routes for key power links such as Estlink 1 and 2.
Raw position history is retained for five days. Events and recorded port calls are kept permanently. Event pages preserve available track samples separately, so an archived event can retain its evidence after raw positions expire. History that expired before archiving began cannot be reconstructed.
Map legend
Vessels
| Red dot | Watched vessel, transmitting now (seen within 15 minutes) |
| Amber dot | Watched vessel, position getting stale |
| Purple dot | Watched vessel that has gone dark, shown at its last known position. In replay mode a hollow purple ghost marks where the signal was lost. |
| Grey dot | Other, non-listed vessel (encounter counterparts, nearby traffic) |
| Blue ring | Currently selected vessel |
| Yellow ring | Location of the event you jumped to |
Infrastructure (the "Infra" toggle)
| Blue lines | Submarine telecom cables. Routes are schematic, especially near shore, where every cable landing in a city is drawn to the same point. |
| Orange lines | Gas and oil pipelines. These are surveyed geometries, for example Balticconnector and Nord Stream. |
| Red lines | Power interconnectors (Estlink 1/2, NordBalt, Fenno-Skan, Baltic Cable, SwePol). Exact routes are not public, so these are approximations with a wide alert margin. |
Other overlays
| Green cells (Coverage) | Areas with sustained AIS reception. This context helps assess a gap, but does not establish why a particular vessel is no longer observed. |
Event types
| Event | What it means |
|---|---|
| Went dark | No position was received for more than six hours in an area with established reception. Known waiting areas can lower the alert priority. The observation does not establish whether the transmitter was switched off. |
| Reappeared | A position was received after an AIS gap. The reported distance is between observations; the route through the gap is unknown. |
| Teleport | The distance between observations would require an average speed above 25 knots. Incorrect or manipulated positions are possible explanations. |
| Encounter | Two vessels remained within 500 metres for at least 30 minutes in relatively quiet surroundings. This describes proximity, not cargo activity. |
| STS suspect | Two vessels came within 300 metres and were both moving slowly for more than 45 minutes. This is a possible ship-to-ship transfer indicator; AIS proximity and speed alone do not confirm a transfer. |
| Identity change | The recorded MMSI, flag, name or call sign changed for an IMO number. Administrative updates and reporting errors can also cause these changes. |
| IMO conflict | Multiple active MMSIs were associated with the same IMO. The event records conflicting reports; it does not determine which identity is correct. |
| Draught change | Reported draught changed by at least half a metre. Recent encounters and port history affect priority. Draught is entered manually and is not a direct measurement of cargo loaded or discharged. |
| Port call | The vessel stayed slow or stationary near a known port for at least two hours. A recorded visit does not identify the cargo or confirm a berth. |
| Infra proximity | The vessel stayed slow or stationary near a mapped cable, pipeline or power link for at least 30 minutes. Port and traffic context filter or lower the priority of routine observations. This does not establish contact with infrastructure or damage to it. |
| New listing | The vessel was added to the tracker’s watch list. Its appearance here may follow the date of the underlying sanctions designation. |
How the noise is kept down
The sea is full of perfectly normal stops, meetings and slow traffic. The tracker first learns what normal looks like and then reports deviations:
- a coverage grid learns where reception is reliable, so dark alerts only use reception history as context;
- a learned anchorage map, built from the behaviour of ordinary non-listed traffic, marks the world's waiting areas, and routine findings inside them are demoted;
- port stays, crowded roadsteads and cable landing zones are recognised and filtered before an alert is raised.
A broad feed interruption pauses new AIS gap detection to reduce false alerts. The ⌖ map button opens a replay around an event. View event opens its shareable page with recorded measurements and available track samples. Gaps remain visible in those tracks. Priority describes the tracker’s alert level, not a probability of wrongdoing.
Limitations
- AIS is self-reported. Names, destinations and draughts are typed in by the crew and can be wrong or deliberately misleading.
- Coverage depends on receiver networks. Gaps on the open ocean are normal.
- Cable routes are schematic and power link routes approximate, so distances to infrastructure are indicative.
- Everything shown here is an indicator built from public data, not an accusation of unlawful activity.
Contact and corrections
To report a problem with Shadowfleet.watch, email contact@shadowfleet.watch. Include the vessel’s IMO or MMSI, the event link if available, the observation time and a source supporting the correction. The cited sanctions provider or issuing authority remains the source for the underlying designation.