How hormuz.now works

Ships broadcast their position, speed, identity and type by AIS, the Automatic Identification System. A single collector on our server reads the public AIS map tiles covering a box from 24°N to 28.5°N and 54°E to 59°E (six tiles per poll) about every 20 seconds, day and night. It runs on its own schedule whether or not anyone is visiting the site. A normal poll returns well over 1,000 vessels; the latest returned 1,505.

1. Snapshot. Each poll updates an in-memory snapshot of every vessel in the box. The live map and the ships page read from it.
2. Crossing detector. Every new position is tested against our counting line. Each crossing is written to a database log with the vessel's name, type, size, flag, declared destination, direction and time.
3. Fleet tracker. A second tracker times how long each commercial ship has been stationary and keeps a sampled track for ships moving near the strait.
4. Report. Once a minute we rebuild one report from the snapshot, the crossing log, the fleet tracker and IMF PortWatch data, which we fetch every six hours. Every number on the site comes from that report, including the status.
5. Serving. Pages and API responses are rendered from the report and cached in memory. Visitors never trigger a request to the AIS source or to PortWatch, so heavy traffic cannot slow the collector.

Satellite positions with no identity (labelled "[SAT-AIS]" on some maps) are ignored, because their IDs change on every poll and a ship cannot be followed from one poll to the next.

Headline counts include only commercial ships: vessels whose AIS type is cargo or tanker and that are at least 80 m long, or at least 5,000 deadweight tonnes when no length is reported. This approximates the vessel types in IMF PortWatch's transit count (tankers, container ships, dry bulk, general cargo and ro-ro).

Tugs, dredgers and other special craft, passenger ferries, fishing boats, pleasure craft, high-speed craft, navigation aids, vessels of unknown type, and cargo ships and tankers under 80 m are left out of the headline figures, though they still appear on the live map. In the last 7 days we logged 32 commercial crossings and 84 crossings by all vessels, including small craft (distinct vessels per direction).

Finer classes (crude, product, chemical, LNG and LPG tankers; container, bulk, general cargo and ro-ro ships) come from a second, more detailed type code, which we trust only when it agrees with the main type. Tanker size classes follow deadweight conventions: VLCC from 200,000 t, Suezmax from 120,000 t, Aframax/LR2 from 80,000 t, Panamax/LR1 from 55,000 t and MR from 25,000 t.

We compare traffic with 84.8 commercial transits a day, 47.6 of them tankers: the IMF PortWatch daily average for the 365 days before the crisis (28 Feb 2025 – 27 Feb 2026). We recompute it from our stored copy of the IMF PortWatch series as the average daily transit count over the 365 days before Day 1, so it updates if PortWatch revises its data.

The 365 days before Day 1 include unusually quiet months (67.4 transits a day in November 2025, 55.5 in December and 58.5 in January 2026), so this baseline sits below the 2022–2024 annual averages of 91.1 to 93.5 a day (IMF PortWatch data, queried 29 Sep 2026). Measured against it, current traffic looks slightly higher as a share of normal than it would against a multi-year average.

Day 1 of the crisis is 28 February 2026; today is Day 216. Some trackers count from a later date, such as 2 March, when the IRGC confirmed the closure (Wikipedia, accessed 29 Sep 2026), so their day number is lower.

Every AIS signal carries a destination typed in by the crew. It has no fixed format: the same port can appear as AEFJR, AE FJR, FUJAIRAH, FUJ OPL or INSIK>AEFJR, and during this crisis many crews use the field for messages instead. We call it the declared destination everywhere, because it can be wrong, out of date or not a destination at all. We never edit it; we decode it in five steps.

1. Clean-up. The text is upper-cased and stray punctuation removed. Blank values and fillers such as 0, CLASS B, N/A, NONE, TBA, TBC, PERSIAN GULF or ARABIAN GULF count as not set.
2. Routes. A route written FROM>TO (or with =>, -> or TO) is read as its last part, and the first part is kept as the origin. If the last part is not a port, as in AE KLF>FOR ORDERS, the whole text is searched instead.
3. Port. We look first for a UN/LOCODE, the five-letter United Nations code for a port (AEFJR is Fujairah), with or without the space, then for a port name or common abbreviation. Our list has about 70 ports: 32 inside the Gulf, 9 on the Gulf of Oman and Arabian Sea coast just outside the strait, and about 30 common destinations further afield, from Yanbu and Karachi to Singapore and Ningbo.
4. Country. With no port match, a country name (UAE, SAUDI, INDIA, CHINA and others) or an unlisted UN/LOCODE written with a space (OM XYZ) gives the country only.
5. Region. Each port is placed inside the Gulf (reached from the open sea only through the strait), on the Gulf of Oman coast outside the strait, or beyond the region. A country on its own counts as beyond the region, except the eight Gulf states (the UAE, Oman, Iran, Iraq, Kuwait, Qatar, Bahrain and Saudi Arabia), which we leave as side unknown.

For every crossing we keep the destination the ship declared at that moment, so the traffic page can show where ships that crossed in the last 7 days said they were going (each ship counted once per direction). The ships page decodes the destinations of every commercial ship in the region now.

For commercial ships moving at 1 knot or more within 150 km of the counting line, we store at most one position every 5 minutes per ship: time, position, speed and course. Samples are written to our database in batches and deleted after 7 days. Stationary ships are not sampled (their waiting time is recorded instead), and position reports more than 6 hours old are skipped.

Each vessel page draws the ship's track for the last 7 days; the vessel API returns the last 48 hours. A gap in a track means we had no fresh position: the ship was stationary, outside the 150 km radius, or silent.

Dark ships

Ships of 300 gross tonnes and above on international voyages must carry AIS, but a master may switch it off when broadcasting would compromise safety or security (IMO, accessed 29 Sep 2026; IMO Resolution A.1106(29)). Many ships cross Hormuz dark during this crisis: on 27 September 2026 Windward counted 14 of 24 transits with AIS off (Windward, data as of 28 Sep 2026). A ship that goes dark and reappears on the other side is still counted by our side memory, unless the gap exceeds 72 hours; a ship that stays dark is not counted at all. We list ships near the strait that have gone quiet as AIS-silent.

GNSS jamming and spoofing

Jamming and spoofing of satellite navigation can place ships in the wrong position, on land or jumping across the water. Windward reported 110 vessels affected by GPS jamming on 28 September 2026 (Windward, data as of 28 Sep 2026). We discard positions on land and jumps faster than 40 knots, and the 2 km band absorbs jitter near the line, but a consistently spoofed track can still be wrong.

Warships and escorts

Most warships do not broadcast AIS, and those that do are normally left out by our commercial filter, which keeps only cargo ships and tankers. Merchant ships crossing under naval coordination are counted only if their AIS is on.

Coverage limited to our box

We see only 24–28.5°N and 54–59°E. That covers the strait, Dubai and Jebel Ali, Fujairah, Khor Fakkan, Bandar Abbas and Sohar, but not upper-Gulf ports such as Ras Tanura, Kuwait or Ras Laffan, so fleet and waiting counts describe our area, not the whole Gulf. Crossing counts are unaffected, because the line sits well inside the box. Ship type, size and declared destination are self-reported in AIS and can be wrong or missing.

Reconstructed history

Our crossing log starts on 20 April 2026. The live tracker described on this page recorded its first counted crossing on 28 September 2026; crossings before that are reconstructed from an earlier tracker that stored only a few positions per ship inside a smaller box (26.10–26.95°N, 55.95–56.95°E). They are estimates and can miss crossings north-east of that box. Reconstructed crossings are marked "est." in tables; days counted entirely by the earlier tracker are drawn hatched in charts and labelled legacy in the daily dataset (mixed when both trackers contributed).

Fujairah bunkering and "waiting" ships

Fujairah, on the UAE's east coast just outside the strait, is a major bunkering hub where tankers refuel (Baird Maritime, 22 Jul 2025). Ships stationary there may be refuelling, loading or waiting for orders rather than queuing for the strait, so our count of commercial ships waiting on the Gulf of Oman side (479 now) can overstate the queue for the strait. Ships that approach and turn back without crossing the line are not counted as transits.