By Remi Cruttenden (Associate), Richard Soyoye (Associate), Daniel Martin (Partner) and Ruth Allan De Maldonado (Knowledge Counsel) at HFW

Having examined the navigational and contractual implications of GPS jamming and AIS spoofing in Parts 1 (“Collisions and groundings”) and 2 (“Charterparties”) of this briefing mini-series, this third instalment examines sanctions-related risks and the consequential cargo issues that can arise where vessel identity or location data is manipulated.

AIS spoofing frequently arises in a sanctions context, particularly where vessels seek to conceal calls at high-risk ports to load and/or discharge sanctioned cargoes, most notably Russian, Iranian and Venezuelan oil.

For example, vessels in South America have reportedly lifted over US$1 billion - worth of Venezuelan oil while spoofing AIS signals to ostensibly appear as though they are instead loading bitumen from Brazilian ports.

In recent months we have seen the US take an aggressive stance against sanctions breaching operations, for example, with oil tankers Skipper and Centuries both being seized by US forces after loading Venezuelan oil while AIS spoofing.

These sanctions-compliance risks have been vividly illustrated by the ongoing US–Iran conflict. Since the outbreak of hostilities in late February 2026, GPS jamming and AIS spoofing have affected numerous vessels operating in and around the Strait of Hormuz (through which approximately 20 per cent to 25 per cent of the world’s seaborne oil transits), with many innocent commercial vessels simultaneously going “dark” for safety reasons. This has created compliance profiles indistinguishable from deliberate sanctions evasion. The US declared a naval blockade of Iranian ports effective 13 April 2026, prompting counter-seizures by Iran’s Islamic Revolutionary Guard Corps of merchant vessels, including MSC Francesca and Epaminondas, and leaving approximately 1,550 vessels stranded in the Persian Gulf. In the year before the latest outbreak of hostilities, reports suggest that over half of liquid petroleum gas cargoes purportedly loaded in Iraq between January 2024 and February 2025 may have in fact been loaded in Iran.

The US response in connection with Venezuela has led to numerous vessels in Venezuelan waters now spoofing their AIS to display locations even further afield, in Africa, Europe or Asia. Further, complex AIS identity fraud by sanctioned vessels, whereby a sanctioned vessel adopts the AIS identity of another vessel, has led the US Office of Foreign Assets Control (OFAC) to target non-breaching vessels in error.

While those involved in sanctioned trades are often aware of the true origin of the cargo, this is not always the case. For example, an unwitting owner may be ordered by its charterer to load “Iraqi” oil from a storage vessel via ship-to-ship (STS) transfer in Iraqi waters, unaware that the storage vessel had in fact lifted Iranian oil, while spoofing its AIS data to appear as though it was loading offshore Iraq.

Such AIS spoofing typically comes to light later, often through investigations by pressure groups such as United Against Nuclear Iran, which use satellite imagery to expose the deception. Maritime data providers such as Lloyd’s List Intelligence are frequently able to identify vessels indirectly involved, or one or two steps removed from, the STS operation; while the UN Panel of Experts may play a role in uncovering similar conduct, where UN sanctions target illicit exports, for example from Libya.

Where there is a relevant jurisdictional nexus, owners could be in breach of EU, UK, US or other applicable sanctions. Owners will then need to take legal advice on the best way to engage with sanctions authorities to minimise their own exposure.

OFAC and the US Department of Justice have previously ordered vessels identified as carrying Iranian oil to proceed to the US and discharge cargoes there as part of enforcement actions, and in order to avoid being sanctioned. If the vessel has US trade connections or exposure, there will be significant regulatory and commercial pressure to comply with such orders.

However, compliance with such directions may lead to concerns as to owners’ liabilities to the contractual receiver of the cargo under bills of lading, including potential claims for conversion or for misrepresenting the origin of the cargo.

AIS spoofing therefore carries a significant risk from a sanctions perspective. Bad actors have become increasingly skilled at obscuring the true locations of vessels and sources of cargo, meaning that parties need to be increasingly vigilant when operating in high-risk areas.

As AIS manipulation techniques continue to evolve, stakeholders should remain alert to the associated sanctions risks and ensure that appropriate risk-based compliance procedures and contractual protections are in place when engaging in higher-risk trades or jurisdictions. Enhanced due diligence and early investigation of inconsistencies in vessel movements or cargo origin may assist in mitigating potential regulatory and commercial exposure.

Remi Cruttenden (Associate), Richard Soyoye (Associate), Daniel Martin (Partner) and Ruth Allan De Maldonado (Knowledge Counsel) at global law firm HFW.

This article first appeared on HFW’s website and is reproduced here with permission from the firm.