Maritime court criticizes illegal seizure of oil tanker in West African piracy scare

A suspected pirate ship, a panicked crew and a three-month detention off West Africa ended Wednesday with an international maritime court ruling that Equatorial Guinea illegally seized and held a giant oil tanker.

The International Tribunal for the Law of the Sea largely sided with the Marshall Islands, the flag state of the M/T Heroic Idun, a massive crude carrier detained in 2022 after Nigerian authorities accused it of trying to illegally load oil near one of the country's offshore terminals.

The International Tribunal for the Law of the Sea, based in Hamburg, Germany, was created in the 1990s under the U.N. Convention on the Law of the Sea, the global treaty governing shipping lanes, maritime borders and disputes at sea. More than 160 countries and the European Union are parties to the convention. Instead of going before the tribunal's full bench, the Heroic Idun dispute was handled by a five-judge special chamber created specifically for the case after both governments agreed to bypass arbitration.

Judges found that Equatorial Guinea violated international law by intercepting the tanker in the exclusive economic zone of São Tomé and Príncipe and forcing it to change course under naval escort. The chamber said the Equatoguinean naval vessel "caused the M/T 'Heroic Idun' to change its intended course … by threatening the use of force" and that this "constitutes a breach of the freedom of navigation, unless justified by the convention or other international treaties."

The court also ruled that Equatorial Guinea unlawfully detained the vessel and crew and improperly imposed a fine of more than 2 million euros ($2.3 million) on the ship's captain.

Equatorial Guinea had argued the operation was part of a regional anti-piracy crackdown in the Gulf of Guinea, one of the world's busiest oil shipping routes. Judges rejected that defense, writing "there was no credible basis for the contention that the Republic of Equatorial Guinea was undertaking an anti-piracy operation vis-à-vis the 'Heroic Idun'." The chamber also said it "does not find that the evidence adduced by Equatorial Guinea provides adequate grounds to justify the seizure of the M/T 'Heroic Idun' on suspicion of piracy."

Back in August 2022, the Heroic Idun was waiting near Nigeria's Akpo offshore oil terminal when a vessel identifying itself as the Nigerian navy approached. According to officials in the court record, the crew feared they could actually be pirates posing as naval officers, a familiar threat in the Gulf of Guinea. The tanker raised a piracy alert and pulled away, while Nigerian authorities accused it of trying to load crude oil without authorization.

Days later, Equatorial Guinea intercepted the vessel in waters off São Tomé and Príncipe. Naval officers ordered the tanker to cut its engines and follow them to anchorage in Luba, warning they had "orders to shoot" in case of any "suspect operation."

The ship arrived in Equatorial Guinea on Aug. 13, 2022, and remained there for nearly three months while part of the crew was transferred to a detention facility in Malabo. In November 2022, Equatorial Guinea handed the ship and crew over to Nigerian authorities, who held them until May 2023 before finally releasing them.

Equatorial Guinea argued that its navy acted lawfully under the Yaoundé Code, a regional security pact meant to help West and Central African countries coordinate against piracy, oil theft and other maritime crime.

The judges acknowledged the region's security problems and recognized the Yaoundé framework as an important cooperation tool. But they said anti-piracy operations still have legal limits and cannot be used as a blanket justification for stopping and seizing foreign commercial ships.

Seline Trevisanut, a research professor of international law at KU Leuven, said the ruling sends one of the strongest recent signals yet about where coastal states hit the legal limit when chasing suspected maritime crime. She said the judges treated the forced rerouting of the Heroic Idun under threat of force as a key turning point in the case and made clear that regional anti-piracy deals like the Yaoundé Code cannot be stretched into a free pass for stopping foreign commercial ships.

Trevisanut also said the tribunal took an unusually broad view of the detention itself, treating the entire confinement of the vessel and crew as part of a "continuing wrongful international act" that began the moment the tanker was intercepted and redirected. Even without directly ruling on human rights claims, she said, the judges still emphasized that "considerations of humanity" apply during maritime enforcement operations, a point likely to echo in future disputes over how crews are treated at sea.

Piracy attacks in the Gulf of Guinea have dropped sharply in recent years, but the region remains one of the world's busiest oil shipping corridors, and governments there still face heavy pressure from the United Nations, European governments and shipping companies to crack down on crude theft, armed robbery and smuggling networks at sea.

Ifesinachi Okafor-Yarwood, a lecturer in sustainable futures at the University of St. Andrews and vice chair of UNESCO's African and Adjacent Island States Ocean Decade Taskforce, called the judgment "a watershed moment for maritime security governance" in the Gulf of Guinea.

She said the case exposed a growing contradiction in the region: Coastal states are pushed to aggressively crack down on piracy, oil theft and maritime crime, yet face international legal backlash when those operations target foreign commercial vessels.

Okafor-Yarwood said the judges ultimately prioritized freedom of navigation and flag-state protections over "the practical realities of Gulf of Guinea law enforcement," despite mounting pressure on regional governments to secure shipping lanes critical to the global oil trade.

She also said the ruling could complicate future regional operations because the judges treated Equatorial Guinea's actions separately from Nigeria's request for assistance, signaling that countries can face independent international liability for enforcement actions carried out on behalf of neighboring states.

"What makes these recurring disputes so significant is that they emerge in an environment where the EU and other Western powers routinely frame the GoG as a global security threat that requires stronger local policing," she said. "Yet, when regional states step up to act, their measures become subject to international legal challenge."

The Marshall Islands had sought nearly $55 million in damages, plus repayment of a separate 2 million-euro fine imposed on the ship's captain during the detention, worth about $2.33 million.

Judgments issued by special chambers of the tribunal are final and binding, leaving no formal appeal route for either Equatorial Guinea or the Marshall Islands. Lawyers representing both governments did not immediately respond to requests for comment after Wednesday's ruling, which is likely to become a major reference point for future maritime enforcement disputes in West Africa.

Courthouse News reporter Eunseo Hong is based in the Netherlands.