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For now, all eyes are on the Strait of Hormuz in the war between the US and Iran.
Iran effectively blocked the strait after it was attacked by the US and Israel on February 28, choking off a significant chunk of oil and gas supplies and causing a surge in energy prices.
As part of a ceasefire deal reached on April 8, Iran was expected to reopen the waterway. But Tehran claimed continuing attacks on Lebanon breached the ceasefire conditions, and maintained its blockade. It has also threatened to impose tolls on ships passing through the strait.
The US this week announced its own blockade to prevent ships and tankers moving to and from Iranian ports. Since then, there have been varying reports about whether or not vessels are passing through the strait.
The data shows a “fragmented operating environment rather than a fully enforced blockade”, Dimitris Ampatzidis, maritime risk and compliance manager at Kpler, told The National.
Are ships sailing through?
“We’ve seen that some vessels are still transiting, but at very low volumes,” said Mr Ampatzidis.
Ship-tracking data indicates that only a handful of vessels have crossed recently, peaking at around a dozen per day during the crisis, compared to well over 100-130 daily transits under normal conditions. Multiple vessels have also reversed course or delayed movements, he said.
“What we’re seeing is not a complete shutdown, but selective and risk-based transit behaviour. Some ships, often with stronger risk tolerance or specific affiliations, continue moving, while others are holding back or rerouting.”
The US Central Command said on Wednesday that 10 vessels had been turned around and no ships had broken through since the start of America's blockade on Monday.
On Tuesday, an Iranian-flagged cargo vessel tried to evade the US blockade after leaving Bandar Abbas, exiting the Strait of Hormuz, and transiting along the Iranian coastline. “The guided-missile destroyer USS Spruance (DDG 111) successfully redirected the vessel, which is heading back to Iran,” Centcom said on Wednesday.
However, Iran's Fars News Agency also said on Wednesday that a US-sanctioned Iranian supertanker crossed the strait. The report did not provide details about the tanker or where it was heading.
Chinese-owned Rich Starry, which had been expected to be the first US-sanctioned vessel to make the crossing, reversed back after initially sailing through the waterway on Tuesday.
According to LSEG shipment data provided to The National on Wednesday, four Iranian-flagged vessels crossed the strait since the blockade was imposed on Monday evening. Container ships Kashan, Rayan, Daisy and Golbon made the crossing on Tuesday. Other non-Iranian vessels also crossed the strait, including LPG carriers, oil tankers and container ships, the data showed.
On Thursday, Bloomberg also reported that at least two US-sanctioned, Iran-linked vessels went through the strait, taking a potentially new route from the UAE.
Liquefied petroleum gas carrier G Summer, a Chinese-owned vessel, passed between Iran’s Larak and Qeshm islands late on Wednesday afternoon, while indicating Iraq as its destination, Bloomberg reported. Meanwhile, another sanctioned crude carrier, Hong Lu, took the same route.
The ships arrived off Fujairah earlier this week, before moving north-east across the Gulf of Oman to the Iranian coastline on Wednesday, then northward into Hormuz, the report added.
“At sea, vessel-level behaviour reflects a fragmented picture,” maritime AI company Windward said in a note on Wednesday. “Some vessels are reversing course, others are drifting after clearing the strait, while some continue operating under reduced visibility or inconsistent routing patterns.
“The operating environment is entering an active enforcement phase, where compliance, evasion, deceptive shipping practices and continued limited movement are all occurring simultaneously.”
Spoofing concerns
Data collection and the flow of information is also being affected by “spoofing” – transmitting false data to misrepresent a vessel’s identity or location.
There are two main types of spoofing, according to MarineTraffic. GNSS (Global Navigation Satellite System) spoofing is typically caused by external entities, such as military or state-level players.
They “emit counterfeit GPS-like signals to deceive a ship’s on-board navigation systems”, which can “confuse both the vessel and external tracking systems, placing the vessel in an incorrect position”.
GNSS spoofing is commonly seen in war zones, military exercises or geopolitical hotspots, and may affect multiple vessels simultaneously.
Meanwhile, AIS (Automatic Identification System) spoofing is usually conducted by the vessel itself or its operator. It involves intentionally transmitting false messages including fake GPS co-ordinates, wrong vessel identity (name, call sign) and “duplicate transmissions to simulate 'ghost' ships or mislead tracking systems”.
This is typically done to “hide real movements and evade detection”, according to MarineTraffic.
Spoofing is a major factor complicating the picture at present, Mr Ampatzidis said.
“GNSS spoofing can make vessels appear to be in locations where they are not, or create false transit signals entirely. In fact, hundreds of vessels have shown AIS anomalies in the strait during recent weeks,” he said.
“This means that raw tracking data alone doesn’t always reflect reality. You need to layer behavioural analytics, voyage history and cargo intelligence to understand what is genuinely happening.”
A report by the New York Times on Wednesday cited experts as saying that more and more Iranian-linked ships have been using spoofing in recent days.
The note by Windward also highlighted some ships adopting such methods. The Christianna, a Liberia-flagged Panama bulk carrier went dark for approximately 15 hours, while Elpis, a “falsely flagged and US-sanctioned tanker” transited outbound through the strait on April 13 and went dark after clearing into the Gulf of Oman, it said.
Key chokepoint
The Strait of Hormuz, through which about a fifth of the world's oil and gas supply normally passes, lies between Iran to the north and Oman and the UAE to the south. The waterway is about 54km wide at its narrowest point and consists of 3.7km navigable channels for inbound and outbound shipping as well as a 3.7km buffer zone.
An average of 20 million barrels per day of crude oil and oil products were shipped through it in 2025, according to the International Energy Agency.
Hormuz is also crucial for other exports – about one-third of the world's fertiliser trade normally passes through the waterway.
The Gulf region is a vital supplier of urea and other ingredients in fertiliser production, including nitrogen and sulphur. Liquefied natural gas, another important energy source, is also a critical feedstock for fertiliser production.
The strait is also a major route for trading in food and medicines.
What next?
Iran sees the Strait of Hormuz as its main leverage at the negotiation table, said Nasser Khdour, of Armed Conflict Location and Event Data (Acled), a US-based group that tracks conflicts around the world.
“In the short term, neither Iran nor Washington is likely to want a return to a wider war, especially while diplomacy is still under way. US concessions could push Iran to soften its position over the Strait of Hormuz and the negotiation framework,” said Mr Khdour, who is Middle East assistant research manager at Acled.
Mr Ampatzidis emphasised that, based on Kpler flow data and historical disruption patterns, the key factor is confidence rather than clearance for shipping to resume.
“Even if tensions ease quickly, flows typically don’t normalise immediately. There’s usually a lag as insurers reassess risk, war risk premiums stabilise, and operators regain confidence,” he said.
“In practical terms, you’re likely looking at several days to a few weeks before traffic meaningfully recovers, and longer if GNSS spoofing, security risks or unclear enforcement conditions persist,” he added.
