Note: Crossing dates represent estimated Strait of Hormuz transit windows derived from AIS and other verification sources. Vessels listed and timestamps may be revised as additional information becomes available.
Detection Methods
Kpler monitors vessel movements through the Strait of Hormuz by utilizing a combination of direct AIS observations and expert-led transit reconstructions.
Transit Detection
Our methodology ensures comprehensive coverage of the chokepoint by addressing both active and inactive signals:
Observed Crossings: When AIS signals are available, a transit is recorded as a vessel moves between the Gulf of Oman and the Mideast Gulf in either direction.
Reconstructed Passages: In instances where AIS signals are missing, disabled or spoofed near the chokepoint, transits are identified through route reconstruction and the application of refined estimation rules.
Current Operational Approach
Due to ongoing AIS disruption and GNSS interference affecting vessel signals in the region, Strait of Hormuz transit identification is currently analyst-validated.
During this period, Kpler analysts manually confirm and record vessel crossings using AIS observations, route reconstruction techniques, and additional verification sources. This process ensures that only confirmed and validated crossings are reflected in the dataset while automated detection methods are temporarily suspended.
Methodological Note on Timestamps
Transit timestamps are derived from observed AIS data where available, and from verified transit events when AIS coverage is incomplete.
In cases where AIS data is unavailable, passage times are estimated using vessel movement patterns and conservative timing assumptions. These estimates may incorporate satellite imagery timestamps, together with the vessel’s last known position inside and outside the Mideast Gulf.
Using these datapoints, Kpler analysts reconstruct the most probable transit window through the Strait of Hormuz based on the vessel’s expected route and speed between known positions.
Accordingly, these timestamps should be interpreted as a validated transit window through the Strait of Hormuz, rather than an exact crossing time.
Transit timestamps may be revised as additional information becomes available. In particular, passages for vessels operating without AIS (“dark” vessels) may be inserted or refined retroactively when new confirmation data—such as imagery or other verification sources—is obtained.
Key Insight: This approach ensures that even "dark" vessel activity is captured in our Mideast Gulf Cargo Flows data, providing a complete picture of maritime traffic through this critical chokepoint.
Accessing data via API
Users can get the list of vessels crossing the Strait of Hormuz, their IMO, the crossing date and a proxy of loading state via this API call:
https://api.kpler.com/v1/port-calls?zones=Strait of Hormuz&columns=all&startDate=2026-01-01&withEmptyVolume=true
The proxy of the loading state is the Id (Voyage) column.
If null, the vessel is ballast.
If not null, the vessel is loaded.
The information on dead_weight, build_year, flag name of the vessel is available on the Vessel endpoint:
https://api.kpler.com/v1/vessels?columns=all
To know the cargo type of the laden vessels, users can retrieve the cargo onboard the list of vessels returned via the port_call API call on the crossing date with the fleet-metrics/vessels endpoint:
http://api.kpler.com/v1/fleet-metrics/vessels?metric=loaded_vessels&zones=Mideast Gulf, Gulf of Oman&unit=kb&startDate=2026-03-01