Strait of Hormuz: frequently asked questions

As of 1 October 2026, 05:36 UTC, hormuz.now's live status for the Strait of Hormuz is Restricted. AIS-visible commercial traffic is about 5% of normal: 4.6 a day over the past week, against 84.8 before the crisis. Ships are crossing under US naval coordination; Iran claims control and requires transit permits; the official threat level is severe.

The label is computed from live AIS ship positions using a published rule; an editor can pin it only for an official declaration or a data outage, and a pinned status carries a visible note. The traffic page lists every crossing.

Sources: IMF PortWatch: Strait of Hormuz, 29 September 2026 · JMIC Advisory Update 100 (UKMTO), 27 September 2026 · RFE/RL via GlobalSecurity (CENTCOM), 16 September 2026

Our live status is currently Restricted, with 4.6 AIS-visible commercial crossings a day over the past week (about 5% of the pre-war normal). The two sides describe it differently: Iran declared the strait closed to “hostile” shipping when the war began on 28 February 2026 and requires transit permits through its Persian Gulf Strait Authority, while US Central Command said on 16 September that it “remains open for transit”. As of late September 2026, ships cross either through a US-coordinated southern corridor in Omani waters or with Iranian permits, and many do so with AIS switched off. The news page tracks the latest developments.

Sources: Wikipedia: Persian Gulf Strait Authority, 29 September 2026 · RFE/RL via GlobalSecurity (CENTCOM), 16 September 2026 · Windward daily intelligence, 28 September 2026

Today is day 216 of the crisis, counting 28 February 2026, when US and Israeli strikes on Iran began, as day 1. The IRGC officially confirmed the closure on 2 March 2026, which is why some trackers show a count two days lower. Traffic has not returned to normal since: the busiest month since the war began, June 2026, averaged 12.9 AIS-visible transits a day on IMF PortWatch's count, against 84.8 a day in the year before the war. Our live status is currently Restricted, and the timeline lists the key events.

Sources: Wikipedia: 2026 Strait of Hormuz crisis, 29 September 2026 · GlobalSecurity: Iran war daily report, 29 September 2026 · IMF PortWatch: Strait of Hormuz, 29 September 2026

The disruption began on 28 February 2026, when the United States and Israel launched strikes on Iran and Iran declared the strait closed to “hostile” shipping; attacks on merchant ships started on 1 March, and the IRGC confirmed the closure on 2 March. The Islamabad Memorandum of 17 June brought a partial reopening, but the ceasefire collapsed on 8 July and the US reimposed its naval blockade of Iranian ports from 14 July. Iran links a full reopening to the US lifting that blockade, waiving oil sanctions and releasing frozen funds. Our live status is currently Restricted, and the timeline has every dated event.

Sources: Wikipedia: 2026 Strait of Hormuz crisis, 29 September 2026 · Wikipedia: Persian Gulf Strait Authority, 29 September 2026 · Wikipedia: 2026 United States naval blockade of Iran, 29 September 2026 · PBS NewsHour, 26 September 2026

There is no agreed date. Iran's foreign minister outlined a seven-day plan at the UN in New York on 24–25 September 2026: the US would lift its blockade, waive oil sanctions and release frozen funds, and the strait would reopen with talks starting within seven days. President Trump rejected it on 26 September, saying the deal “would not be acceptable”. Qatar held separate talks with both sides in New York on 28–29 September, and on 29 September Iran said it was awaiting a US reply to an amended proposal. Follow the reopening talks and our live status.

Sources: PBS NewsHour, 26 September 2026 · NPR, 26 September 2026 · IRNA via GlobalSecurity, 29 September 2026

The label is computed from our AIS crossing log using a published rule. Open needs a 7-day average of at least 60 commercial crossings a day on an IMF PortWatch-equivalent basis (the threshold prediction markets use for a return to normal), a JMIC threat level of MODERATE or lower, and no closure in force. Closed means no commercial crossing for 48 hours, or under 10% of normal traffic while a closure is declared and no protected corridor operates; everything in between is Restricted, and a new level must hold for an hour before it replaces the old one. Right now the 7-day average is 4.6 a day (about 5% of the 84.8 pre-war normal) and the JMIC threat level is SEVERE. Editors can pin the status only for an official declaration or a data outage; full details are in our methodology.

Sources: IMF PortWatch: Strait of Hormuz, 29 September 2026 · JMIC Advisory Update 100 (UKMTO), 27 September 2026

AIS-visible commercial crossings so far today (UTC): 0. In the last 24 hours: 9, of which 2 inbound (westbound, into the Gulf) and 7 outbound (eastbound, to the Gulf of Oman). The most recent crossing we detected was XIN HAI TONG 29, outbound, 14 hours ago. We count cargo ships and tankers of at least 80 m with AIS switched on, so ships running dark are missed; the traffic page lists every crossing.

Source: hormuz.now live AIS data as of 1 Oct 2026, 05:36 UTC (how we count)

AIS-visible commercial crossings yesterday (UTC): 10. Last 7 days: 32, an average of 4.6 a day, with tankers accounting for 16; last 30 days: 135. IMF PortWatch, which publishes with a lag of several days, recorded 3.1 transits a day in the 7 days to 27 September 2026. Daily totals since 20 April 2026 are charted on the traffic page.

Source: IMF PortWatch: Strait of Hormuz, 29 September 2026

It depends on who is counting. IMF PortWatch, which counts tankers, container ships, bulk carriers, general cargo and ro-ro vessels from AIS, recorded 84.8 transits a day in the 365 days before the war (28 February 2025 to 27 February 2026), including 47.6 tankers, and 91–94 a day in 2022–2024. Counts that include more vessel types, or ships not broadcasting AIS, run higher. hormuz.now uses PortWatch's pre-war average as its baseline; the current 7-day average of 4.6 a day is about 5% of it (traffic before the war).

Source: IMF PortWatch: Strait of Hormuz, 29 September 2026

AIS-visible tanker crossings: 6 in the last 24 hours and 16 in the last 7 days. Before the war about 47.6 tankers a day crossed on IMF PortWatch's count, more than half of all transits, but in September 2026 PortWatch saw about one AIS-visible tanker a day. Oil volumes have recovered much more than AIS tanker counts suggest, as the oil page explains.

Sources: IMF PortWatch: Strait of Hormuz, 29 September 2026 · CNN (Kpler data), 29 September 2026

Over the last 7 days the most common flag among AIS-visible crossings was Panama; the traffic page breaks down all flags and declared destinations. A flag shows where a ship is registered, not who owns it or where its cargo goes. Iran issues transit permits to individual ships through its Persian Gulf Strait Authority, while the US Navy coordinates transits through a southern corridor in Omani waters. Iran has blacklisted 81 ships for using that corridor or crossing without paying, including three VLCCs linked to Saudi and South Korean operators added on 28 September 2026 (Windward).

Sources: Windward daily intelligence, 28 September 2026 · Windward: Iran's ship blacklist, 17 September 2026

Every ship broadcasts a declared destination, which we decode into a port, a country and a region: inside the Gulf, the Gulf of Oman coast just outside the strait (Fujairah, Khor Fakkan or Sohar, for example), or beyond. The traffic page breaks down the declared destinations of the 32 AIS-visible commercial crossings in the last 7 days, and the ships page shows where the 799 large commercial ships in the region say they are heading. Destinations are typed by crews and can be out of date, wrong, or a message rather than a port (how we read destinations).

Source: hormuz.now live AIS data as of 1 Oct 2026, 05:36 UTC (how we count)

Right now 1,505 vessels are broadcasting AIS in our coverage area, 799 of them large cargo ships or tankers, including 420 tankers (56 of VLCC supertanker size). Stationary commercial ships: 479 on the Gulf of Oman side of the strait and 163 on the Gulf side, including ships at anchor or in port. The area runs from Abu Dhabi and Dubai to Bandar Abbas, Fujairah and Sohar but does not reach upper-Gulf ports such as Ras Tanura, Kuwait or Ras Laffan, so the Gulf-wide total is higher. The ships page breaks this down by port area, and the IMO says more than 20,000 seafarers in the region are affected.

Source: IMO: Middle East and Strait of Hormuz, 24 September 2026

Right now 479 large cargo ships and tankers are stationary on the Gulf of Oman side of the strait and 163 on the Gulf side (moving at under 1 knot, with a recent AIS position). We time each ship from the position report where it stopped and restart the clock if it drifts more than 3 km, so the ships page can show the median wait at each anchorage, how many ships have waited more than a day or a week, and the longest waits. The longest current wait is at least 28 h. Our clock only started when this tracking began, so a ship that was already at anchor then is shown as waiting “at least” that long. Stationary does not always mean stuck: a ship may be alongside a berth, refuelling at Fujairah or waiting for orders (how we time waits).

Source: hormuz.now live AIS data as of 1 Oct 2026, 05:36 UTC (how we count)

By 23 September 2026 the IMO had counted 83 confirmed incidents and 23 seafarer deaths linked to the conflict. The latest fatal attack on its list, updated on 24 September, hit the bulk carrier Cape Dao off Oman's Musandam Peninsula on 23 September and killed an Indian crew member; no one has claimed it. The IMO also says more than 20,000 seafarers in the region are affected, and 136 vessels with about 2,900 seafarers were evacuated on 23–26 June before evacuations were paused. Recent incidents are listed in our security updates.

Sources: gCaptain, 23 September 2026 · IMO: Middle East and Strait of Hormuz, 24 September 2026

Use our free live ship map, which needs no login. It shows every ship broadcasting AIS in and around the strait (1,505 right now), updated about every 20 seconds, with name, flag, type, speed and declared destination. You can filter by ship category, show only large commercial or moving ships, and search by name, flag or destination. Ships with AIS switched off, and most warships, do not appear.

Source: hormuz.now live AIS data as of 1 Oct 2026, 05:36 UTC (how we count)

No. Ship positions come from AIS, the radio transponder system that IMO rules require on ships of 300 gross tonnes and above on international voyages, and we refresh them about every 20 seconds. Satellite images can reveal ships that are not transmitting, but they are not a continuous live feed. GPS jamming and spoofing can also put a ship in the wrong place on any AIS map: Windward counted 110 vessels affected by GPS jamming on 28 September 2026. See how we count.

Sources: IMO: Automatic Identification Systems, 29 September 2026 · Windward daily intelligence, 28 September 2026

The destination field in a ship's AIS signal is typed by the crew and is meant to name the next port, but during the crisis many ships use it to broadcast a message instead. Many declare the crew's or owner's nationality, such as “CHINESE CREW ONBOARD”; others say that armed guards are on board, that the ship has no link to a party in the conflict, or that it carries food or other humanitarian cargo. Destinations such as “FOR ORDERS” or “OPL” mean a ship is waiting for instructions or waiting outside port limits. The ships page counts how many of the 799 large commercial ships in the region broadcast each kind of message right now. The messages are self-declared, and we cannot verify them (how we read destinations).

Source: hormuz.now live AIS data as of 1 Oct 2026, 05:36 UTC (how we count)

Yes, many are. On 27 September 2026 Windward counted 24 transits of the strait, 14 of them by ships with AIS switched off, while IMF PortWatch, which counts only ships visible on AIS, recorded 1 that day. IMO rules require AIS on ships of 300 gross tonnes and above on international voyages, but a master may switch it off when broadcasting would endanger the ship. Right now 48 large commercial ships within 150 km of our counting line have a last AIS position more than 6 hours old. Our ships page lists them: they may have switched their transponder off, moved out of receiver range or had their signal jammed. Ships that stay dark are missing from AIS-based counts, including ours (AIS-silent ships).

Sources: Windward daily intelligence, 28 September 2026 · IMF PortWatch: Strait of Hormuz, 29 September 2026 · IMO: Automatic Identification Systems, 29 September 2026

Before the war, about 20–21 million barrels a day. The US Energy Information Administration puts the flow at 20.7 million barrels a day in 2024 and 20.9 million in the first half of 2025, about 20% of world petroleum liquids consumption and about a quarter of seaborne oil trade. The IEA's 2025 figure is about 20 million barrels a day, including nearly 15 million of crude, around 34% of global crude trade. Most of it goes to Asia: in the first half of 2025, 89% of the crude went to Asian markets, and China, India, Japan and South Korea took 74%. The oil page shows what is moving now.

Sources: EIA: World Oil Transit Chokepoints, 3 March 2026 · IEA: Strait of Hormuz, February 2026

Oil volumes have recovered much more than ship counts, but remain below normal. Kpler estimated oil and product flows through Hormuz at 13.1 million barrels a day in the week to about 27 September 2026, against 17.1 million a day before the war on its measure (CNN, 29 September). Estimates vary widely by source and period, partly because many tankers cross with AIS switched off. On AIS, tanker crossings numbered 6 in the last 24 hours and 16 in the last 7 days; the oil page has the details.

Source: CNN (Kpler data), 29 September 2026

IMF PortWatch publishes the combined deadweight of the tankers that cross the strait each day: their carrying capacity, not the oil actually on board, and only for tankers visible on AIS. Our oil page charts it as a 7-day average against the pre-war level: over the latest 7 days of data it was 1% of that level. PortWatch publishes with a lag, and its latest day is 27 September 2026. Before the war about 47.6 tankers a day crossed on PortWatch's count. Because many tankers now cross with AIS switched off, sources that also track dark ships see far more oil moving: Kpler estimated oil and product flows through Hormuz at 13.1 million barrels a day in the week to about 27 September 2026 (CNN, 29 September). Our methodology explains how tanker tonnage is measured.

Sources: IMF PortWatch: Strait of Hormuz, 29 September 2026 · CNN (Kpler data), 29 September 2026

About one-fifth of global LNG trade passed through Hormuz before the war, mostly from Qatar: 11.4 billion cubic feet a day in the first half of 2025 (EIA). Very little has moved since the war began: Qatar exported 18 LNG cargoes in the first six months of the war, against 509 a year earlier (Euronews). On 28 September 2026 QatarEnergy extended force majeure through November for buyers in Pakistan and Bangladesh and to early December for Italy's Edison. AIS-visible LNG carrier crossings in the last 7 days: 0, plus 1 by LPG carriers (Hormuz LNG).

Sources: EIA: World Oil Transit Chokepoints, 3 March 2026 · Euronews, 29 September 2026 · The National, 28 September 2026

Only partly. Saudi Arabia's East-West pipeline to the Red Sea port of Yanbu and the UAE's Habshan–Fujairah line to the Gulf of Oman together offer about 4.7 million barrels a day of capacity to bypass the strait (EIA), and the IEA estimates 3.5–5.5 million a day is usable, against about 20 million a day that normally crosses the strait. Drone attacks halted the East-West pipeline on 13 September 2026, and pumping restarted at a low rate on 22 September. The oil page covers the bypass pipelines.

Sources: EIA: World Oil Transit Chokepoints, 3 March 2026 · IEA: Strait of Hormuz, February 2026 · Hydrocarbon Processing, 22 September 2026

Our Gulf ports page tracks 25 ports with IMF PortWatch data: 12 oil and gas terminals inside the Gulf, such as Ras Tanura, Ras Laffan, Mina al Ahmadi and Kharg Island; 7 container and general ports, such as Jebel Ali; and 6 ports outside the strait, including Fujairah and Yanbu, the outlets of the UAE's Habshan–Fujairah and Saudi Arabia's East-West bypass pipelines. For each port it compares port calls and estimated exports over the latest 30 days of data with the year before the war. PortWatch estimates these figures from AIS and publishes them several days late, so every port shows the date of its latest data, and ships with AIS switched off are missed (how we compare ports).

Sources: IMF PortWatch · EIA: World Oil Transit Chokepoints, 3 March 2026

Brent crude rose above $100 a barrel on 8 March 2026 for the first time in four years, and physical Dated Brent later reached an all-time high of $144 (IEA). Brent briefly dipped below $100 on 22 September and was trading at about $103–105 a barrel on 29 September 2026. Prices move with each shift in the talks, the attacks and the flow estimates; the oil page tracks oil prices and insurance.

Sources: Wikipedia: 2026 Strait of Hormuz crisis, 29 September 2026 · IEA commentary, 22 June 2026 · The National, 22 September 2026 · GlobalSecurity: Iran war daily report, 29 September 2026

The oil and gas shortfall persists and the costs spread. IEA members committed 426 million barrels of emergency oil stocks in March 2026, the largest collective action in the agency's history, and the Saudi and UAE bypass pipelines can carry only part of the oil that normally crosses the strait. LNG buyers face winter with Qatari supply still under force majeure, and war-risk insurance has run at 3–10% of a ship's hull value, against about 0.25% before the war (Marsh, July 2026). The oil page follows the economic impact.

Sources: IEA: collective action to release oil stocks, 19 March 2026 · The National: LNG force majeure, 28 September 2026 · The National: war-risk premiums, 17 July 2026

The Strait of Hormuz is the narrow sea passage between Iran and Oman that links the Persian Gulf with the Gulf of Oman and the Arabian Sea. It is the only sea route out of the Persian Gulf, so it carries much of the oil and gas exported by Gulf producers. Before the war about 20 million barrels of oil a day crossed it, about a fifth of world consumption, along with about one-fifth of global LNG trade (EIA). At its narrowest it is 21 nautical miles (39 km) wide; see where the strait is on our map.

Sources: Wikipedia: Strait of Hormuz, 29 September 2026 · EIA: World Oil Transit Chokepoints, 3 March 2026

The strait lies between Iran to the north and Oman's Musandam Peninsula to the south; Musandam is an Omani exclave, separated from the rest of Oman by the United Arab Emirates. It sits northeast of Dubai and connects the Persian Gulf with the Gulf of Oman and the Arabian Sea. Bandar Abbas in Iran and Khasab in Oman are the main towns on either shore, and the UAE's east-coast ports of Fujairah and Khor Fakkan lie just outside it. See the annotated map.

Sources: Wikipedia: Strait of Hormuz, 29 September 2026 · Wikipedia: Musandam Governorate, 29 September 2026

About 21 nautical miles (39 km, or 24 statute miles) at its narrowest point, between Iran's Larak Island and Oman's Great Quoin Island, widening to about 52 nautical miles (97 km). It is about 90 nautical miles (167 km) long. Ships use a traffic separation scheme with one inbound and one outbound lane, each 2 nautical miles (3.7 km) wide, separated by a buffer zone of similar width. See the strait's width, length and depth on our map page.

Sources: IEA: Strait of Hormuz, February 2026 · Wikipedia: Strait of Hormuz, 29 September 2026 · IMO: Middle East and Strait of Hormuz, 24 September 2026

The water is deepest near Oman's Musandam Peninsula and becomes shallower toward the Iranian shore; depths in the southern inshore zone exceed 650 ft (about 200 m) (Strauss Center). A fully laden supertanker draws 20–25 m, so depth does not limit traffic; security and the narrow shipping lanes do. The map page shows the shipping lanes and islands.

Source: Strauss Center: Strait of Hormuz geography, 29 September 2026

The main islands are Hormuz, Qeshm, Larak and Hengam, all Iranian; Qeshm is the largest island in the Persian Gulf. The strait area has eight major islands, seven of them controlled by Iran (Strauss Center). Iran also holds Abu Musa and the Greater and Lesser Tunbs farther west, which it took in 1971 and which the UAE still claims. See the islands on the map.

Sources: Strauss Center: Strait of Hormuz geography, 29 September 2026 · Wikipedia: Qeshm, 29 September 2026 · Wikipedia: Seizure of Abu Musa and the Tunbs, 29 September 2026

In normal times ships follow the traffic separation scheme proposed by Iran and Oman and adopted by the IMO in 1968, which lies in Omani territorial waters. During the 2026 crisis, many ships that cross use a southern corridor in Omani waters coordinated by the US Navy, while Iran directs ships holding its transit permits to its own northern route. Iran has blacklisted 81 ships for using the southern corridor or crossing without paying (Windward, 28 September 2026). The map shows the shipping lanes.

Sources: IMO: Middle East and Strait of Hormuz, 24 September 2026 · Windward: Iran's ship blacklist, 17 September 2026 · Windward daily intelligence, 28 September 2026

No single power does. Iran controls the northern shore and most of the islands, and runs a permit-and-toll system through its Persian Gulf Strait Authority, set up in May 2026. The main shipping lanes lie in Omani waters, where the US Navy coordinates transits through a southern corridor; the US has also blockaded Iranian ports since 14 July 2026 and said it had redirected 122 vessels by 25 September. Iran has blacklisted 81 ships for using that corridor or crossing without paying. The map page explains who controls the strait.

Sources: Wikipedia: Persian Gulf Strait Authority, 29 September 2026 · Army Recognition (CENTCOM figures), 28 September 2026 · Windward daily intelligence, 28 September 2026

Not at its narrowest point. Iran and Oman each claim a 12-nautical-mile territorial sea (Iran since 1959, Oman since 1972), and these overlap, leaving no high seas in between. It is still an international strait, where the UN Convention on the Law of the Sea (UNCLOS) gives ships a right of transit passage that “shall not be impeded”. Iran signed UNCLOS in 1982 but has not ratified it, Oman ratified it in 1989, and the US, which is not a party, treats transit passage as customary law (legal status of the strait).

Sources: Wikipedia: Strait of Hormuz, 29 September 2026 · Just Security, 15 March 2026

Under the prevailing view of international law, no. Transit passage through an international strait cannot be suspended under UNCLOS, and the rule is widely regarded as customary law that binds even non-parties such as Iran and the US (Just Security, 15 March 2026). Iran disputes this: it signed but never ratified UNCLOS and has long argued that only the more limited right of innocent passage applies in its waters. The US Treasury warned on 1 May 2026 that paying Iran for passage risks sanctions.

Sources: Just Security, 15 March 2026 · Wikipedia: Strait of Hormuz, 29 September 2026 · Wikipedia: Persian Gulf Strait Authority, 29 September 2026

Neither Iran nor the US has announced a country-specific reopening for India or Pakistan. Ships of any flag cross at their own risk, either with an Iranian transit permit or through the US-coordinated southern corridor, which can put them on Iran's blacklist. Both countries' energy imports are affected: QatarEnergy's LNG force majeure covers buyers in Pakistan through November and at least one Indian buyer (The National, 28 September 2026). The seafarer killed on the bulk carrier Cape Dao on 23 September was Indian. The traffic page shows the flags of ships crossing each week.

Sources: The National, 28 September 2026 · gCaptain, 23 September 2026 · Windward: Iran's ship blacklist, 17 September 2026

Ships paid no transit toll before 2026; Iran now charges one. In May 2026 Iran set up the Persian Gulf Strait Authority (PGSA) to issue transit permits and collect fees, and the US Treasury, which had warned on 1 May that paying Iran for passage risks sanctions, designated the PGSA on 27 May. On 22 September an Iranian parliamentary committee approved articles allowing seizure of 20% of the cargo of ships that break Iran's rules; the bill still needs a full parliamentary vote and Guardian Council approval. Our news page follows Iran's toll regime.

Sources: Wikipedia: Persian Gulf Strait Authority, 29 September 2026 · US Treasury (OFAC), 27 May 2026 · Iran International, 22 September 2026 · IRNA via GlobalSecurity, 23 September 2026

Mines remain a risk. US officials said on 25 August 2026 that the Navy had cleared mines from the traffic separation scheme and that underwater drones had identified more than 100 suspected mines, and CENTCOM said on 19 September that the primary transit lanes were clear. JMIC still warned on 1 September of drifting or uncharted mines, and its 18 June advisory reported a confirmed mine at about 26.41°N, 56.34°E. See our security updates.

Sources: Wikipedia: 2026 Strait of Hormuz crisis, 29 September 2026 · Fortune (CENTCOM), 19 September 2026 · JMIC Advisory Update 092 (UKMTO), 1 September 2026 · JMIC Advisory Note 009-26 (IMO), 18 June 2026

The risk remains high: JMIC, the multinational maritime security centre, currently rates the regional threat level SEVERE. The IMO counted 83 confirmed incidents and 23 seafarer deaths by 23 September 2026; recent cases include the bulk carrier Cape Dao, hit off Musandam on 23 September with one crew member killed, and LR Stephanie, hit on 21 September with two injured. hormuz.now does not give navigation or security advice; follow UKMTO, JMIC and flag-state guidance. Our security updates list recent incidents.

Sources: JMIC Advisory Update 100 (UKMTO), 27 September 2026 · gCaptain, 23 September 2026 · IMO: Middle East and Strait of Hormuz, 24 September 2026

Much more than before the war. In July 2026 the broker Marsh said war-risk rates for Gulf transits ranged from 3% to 10% of a ship's hull value, against about 0.25% before the war. For a $100 million tanker that is $3–10 million instead of about $250,000. The oil page covers prices and insurance.

Source: The National, 17 July 2026

As of late September 2026, yes. US Central Command began blockading ships going to or from Iranian ports on 13 April 2026, lifted the blockade on 18 June under the Islamabad Memorandum, and reimposed it from 14 July after the ceasefire collapsed on 8 July. CENTCOM said it had redirected 122 commercial vessels as of 25 September. The blockade is separate from the southern corridor through which the US coordinates transits for other shipping; our news page tracks the US blockade.

Sources: Wikipedia: 2026 United States naval blockade of Iran, 29 September 2026 · Army Recognition (CENTCOM figures), 28 September 2026

Not before 2026. During the 1981–1988 Tanker War, Iraq carried out 283 attacks on shipping and Iran 168, but traffic kept moving. In June 2025, after US strikes on Iranian nuclear sites, Iran's parliament voted to back closing the strait; the final decision rested with the Supreme National Security Council, and traffic continued, with IMF PortWatch averaging 102.2 transits a day that month. The timeline's history section covers both episodes.

Sources: Wikipedia: Tanker War, 29 September 2026 · Anadolu Agency, 22 June 2025 · IMF PortWatch: Strait of Hormuz, 29 September 2026

The Tanker War was the campaign of attacks on merchant shipping in the Gulf during the Iran–Iraq War, from 1981 to August 1988; Iraq carried out 283 attacks on shipping and Iran 168, and well over 100 sailors were killed. The US escorted reflagged Kuwaiti tankers in Operation Earnest Will from July 1987. After the frigate USS Samuel B. Roberts struck a mine on 14 April 1988, the US sank Iranian vessels and destroyed two platforms in Operation Praying Mantis. On 3 July 1988 the USS Vincennes shot down Iran Air Flight 655, killing 290 people (history timeline).

Sources: Wikipedia: Tanker War, 29 September 2026 · Wikipedia: Operation Praying Mantis, 29 September 2026 · Wikipedia: Iran Air Flight 655, 29 September 2026

US and Israeli strikes on Iran began on 28 February 2026, and traffic collapsed within days: IMF PortWatch recorded zero transits on 4 March. A ceasefire took effect on 8 April, and the US began blockading Iranian ports on 13 April. The Islamabad Memorandum of 17 June brought a partial reopening: the blockade was lifted on 18 June and PortWatch transits peaked at 51 on 24 June. The ceasefire collapsed on 8 July and the blockade returned on 14 July; attacks, Iran's toll regime and talks have continued since, as the dated 2026 timeline shows.

Sources: Wikipedia: 2026 Strait of Hormuz crisis, 29 September 2026 · Wikipedia: 2026 Iran war ceasefire, 29 September 2026 · IMF PortWatch: Strait of Hormuz, 29 September 2026

The origin is uncertain. One theory links it to a local Persian term, Hur-Mogh, meaning “place of dates”; another links it to Hormoz, the Persian name of the Zoroastrian deity Ahura Mazda. The strait shares its name with Hormuz Island, which sits in it off the Iranian coast (islands on the map).

Source: Wikipedia: Strait of Hormuz, 29 September 2026

We read public AIS vessel positions about every 20 seconds for the waters around the strait (1,505 vessels visible right now) and log every commercial ship that crosses our counting line, with its direction. We count cargo ships and tankers of at least 80 m (or 5,000 dwt when the length is unknown), and our crossing log starts on 20 April 2026. Pre-war comparisons use IMF PortWatch, EIA and IEA figures, each cited with its date, and the live figures on this page are as of 1 October 2026, 05:36 UTC. Our methodology explains how we count crossings.

Source: hormuz.now live AIS data as of 1 Oct 2026, 05:36 UTC (how we count)

They count different things. AIS-only sources such as IMF PortWatch and hormuz.now miss ships that switch off their transponders, and many do in this crisis; commercial trackers such as Windward combine AIS with satellite and other data, and Lloyd's List counts only non-Iranian-linked cargo ships over 10,000 dwt. On 27 September 2026 PortWatch recorded 1 transit while Windward counted 24, 14 of them dark, so AIS-visible counts can undercount real traffic by an order of magnitude. Our advantage is speed: our counts update every minute, while PortWatch publishes days later (why the numbers differ).

Sources: IMF PortWatch: Strait of Hormuz, 29 September 2026 · Windward daily intelligence, 28 September 2026 · Lloyd's List Intelligence, 9 September 2026

A dark ship has switched off its AIS transponder, so it disappears from AIS-based maps and counts, including ours. IMO rules require AIS on ships of 300 gross tonnes and above on international voyages, but a master may switch it off if broadcasting would endanger the ship, and must log it. On 27 September 2026 Windward counted 14 dark ships among 24 transits. GPS jamming, which affected 110 vessels on 28 September according to Windward, can also put ships in the wrong place (limits of our data).

Sources: IMO: Automatic Identification Systems, 29 September 2026 · IMO Resolution A.1106(29), 29 September 2026 · Windward daily intelligence, 28 September 2026

Both use AIS, but PortWatch publishes in weekly batches, so its newest data is several days old. Its latest daily count, for 27 September 2026, is 1, with an average of 3.1 a day over its latest 7 days and 3.7 a day in September 2026. Our own 7-day average is 4.6 a day, and we use PortWatch's pre-war average of 84.8 a day as the baseline for our status. The traffic page charts both series, and our methodology explains the calibration against PortWatch.

Source: IMF PortWatch: Strait of Hormuz, 29 September 2026

Yes. Our daily crossing counts (CSV), daily crossing counts (JSON) and live status (JSON) are free to reuse under a CC BY 4.0 licence: credit hormuz.now with a link. IMF PortWatch publishes its own daily chokepoint data, which we use for pre-war comparisons. Every dataset and API endpoint, with definitions, caching and caveats, is listed on our open data page.

Source: IMF PortWatch: Strait of Hormuz, 29 September 2026