The M/T Heroic Idun (No. 2)

ITLOS Delivers its Largest Ever Compensation Award and Reinforces Freedom of Navigation

The recent judgment of the Special Chamber of the International Tribunal for the Law of the Sea (ITLOS) in The M/T "Heroic Idun" (No. 2), Republic of the Marshall Islands v Republic of Equatorial Guinea marks one of the most significant developments in the law of the sea in recent years.

Beyond awarding more than US$14 million in compensation—the largest damages award ever made by ITLOS—the judgment provides an important reaffirmation of two fundamental principles underpinning the United Nations Convention on the Law of the Sea (UNCLOS): freedom of navigation and exclusive flag State jurisdiction.

Background

The Heroic Idun, a Marshall Islands-flagged VLCC, was waiting offshore Nigeria in August 2022 before loading cargo. After an encounter with what the Master believed could have been a pirate vessel operating without AIS, the tanker proceeded offshore.

Several days later, while located in the Exclusive Economic Zone (EEZ) of São Tomé and Príncipe, the vessel was intercepted by the navy of Equatorial Guinea, diverted to Bioko Island and detained together with her crew. The detention continued for approximately three months before the vessel and crew were transferred to Nigerian authorities, resulting in a total detention period exceeding nine months.

The Tribunal's Findings

The Special Chamber unanimously concluded that Equatorial Guinea's conduct violated multiple provisions of UNCLOS.

Among its principal findings, the Tribunal held that:

• the interception violated the freedom of navigation guaranteed by Articles 87 and 90;

• the exercise of enforcement jurisdiction against a foreign-flagged vessel was inconsistent with the principle of exclusive flag State jurisdiction under Article 92;

• the unlawful detention constituted a continuing internationally wrongful act; and

• the Republic of the Marshall Islands was entitled to substantial compensation for both financial losses and the treatment suffered by the crew.

Perhaps most remarkably, the Tribunal awarded over US$4 million solely for the non-material harm suffered by the crew, recognising that prolonged unlawful detention causes real personal injury beyond purely economic loss.

Why This Judgment Matters

For maritime practitioners, the importance of this case extends well beyond the compensation awarded.

1. Freedom of Navigation Remains Central

The decision reinforces that the EEZ is not sovereign territory.

Although coastal States enjoy sovereign rights over natural resources within their EEZ, those rights do not confer unlimited enforcement jurisdiction over foreign merchant vessels. Freedom of navigation remains the default legal position under UNCLOS.

2. Exclusive Flag State Jurisdiction Has Again Been Confirmed

The judgment continues a line of authorities including the Norstar, San Padre Pio and Enrica Lexie cases, all of which emphasise that interference with foreign-flagged vessels outside territorial seas requires a clear legal basis under international law.

For shipowners and Masters, this provides important reassurance that the Convention continues to protect lawful international navigation.

3. Human Rights and Maritime Law Continue to Converge

One of the more interesting aspects of the judgment is its recognition that unlawful detention affects not only commercial interests but also the welfare of seafarers.

Awarding millions of dollars for non-material damage suffered by the crew reflects an increasing willingness of international tribunals to recognise the human consequences of unlawful maritime enforcement.

4. Coastal State Enforcement Has Limits

The case also serves as a reminder that concerns relating to security, piracy or suspected criminal conduct cannot justify enforcement measures beyond those permitted under UNCLOS.

Even where States cooperate in maritime security, jurisdictional boundaries remain governed by international law.

A Personal Observation

Having previously examined jurisdictional conflicts under UNCLOS during my LL.M. research, I find the Heroic Idun judgment particularly significant because it demonstrates the continued consistency of ITLOS in protecting the balance carefully negotiated within the Convention.

The judgment does not diminish the legitimate interests of coastal States in protecting security or natural resources. Rather, it reinforces an equally important principle: that the international legal order depends upon predictable jurisdictional rules being applied consistently, irrespective of the political or factual complexity of individual cases.

For the offshore industry, shipping companies, insurers and maritime lawyers, the message is clear. UNCLOS continues to provide robust protection for freedom of navigation, and departures from its jurisdictional framework may carry significant legal and financial consequences