A public record of AIS-visible commercial traffic through the strait.
Roughly one in five barrels of seaborne oil passes through the Strait of Hormuz. When that artery seizes, it touches every gas pump, every airline ticket, every container ship rerouted around Africa. This site exists to put that movement — or the absence of it — in front of the public, every day, for free.
Specialist trackers like Lloyd's List, TankerTrackers, and Kpler combine additional commercial feeds and analysis behind paywalls. Hormuz Tracker is a public-facing view of one reproducible source: IMF PortWatch. The pipeline checks for new source data every day and shows the source's latest available observation.
Each morning a small Python pipeline pulls the complete satellite AIS-derived history from the IMF's PortWatch dataset, validates and caches it, then recomputes the rolling averages and a fixed pre-closure baseline. Major geopolitical events are annotated by hand so the data sits inside the story it belongs to.
Methodology
- SourceIMF PortWatch — "Daily Chokepoint Transit Calls and Trade Volume Estimates," chokepoint6 (Strait of Hormuz). Derived from satellite AIS vessel transponders.
- RefreshThe pipeline checks daily via GitHub Actions. PortWatch publishes new observations in batches, so “checked” and “data through” are shown separately.
- CoverageDaily counts go back to January 2019 — over six years of baseline.
- Vessel typesTankers (oil, product, chemical), dry bulk, container, RoRo, general cargo.
- Counting rulePortWatch defines a transit call when a ship crosses the chokepoint boundary. A transit spanning multiple days is counted once, and the same ship is not counted again within 48 hours.
- BaselineThe headline compares the latest seven complete source days with the 365 complete days from February 28, 2025 through February 27, 2026.
- LagThe dataset is delayed and commonly arrives in weekly batches. Always use the displayed “data through” date, not the page-refresh time, to judge freshness.
Caveats
- ScopeThe total covers five commercial categories: tanker, container, dry bulk, general cargo, and ro-ro. It is not a census of military, fishing, tug, service, or other vessel traffic.
- AIS limitationVessels without sufficient AIS observations—including ships operating dark, spoofing positions, or affected by interference—may be absent. During conflict this undercount can be material, so the headline describes PortWatch AIS-visible traffic, not every physical crossing.
- RevisionsRecent observations can be revised by the source. Each rebuild replaces the full local cache and republishes the complete history rather than appending unverified rows.
- Editorial framingEvent annotations are the author's judgment about which dates matter most for context. Reasonable readers can disagree about the framing; the data itself is unfiltered.