The High Seas Treaty has been ratified - what does this means for Environmental Activists and Direct Enforcement?

Laurence Atkin-Teillet, Lecturer at NLS

In 2017, the United Nations General Assembly took a major step toward protecting our oceans by voting to convene an intergovernmental conference. The goal was to establish a legally binding international agreement on the conservation and sustainable use of marine biodiversity beyond national jurisdiction. This was seen as essential, since the UN Convention on the Law of the Sea did not adequately cover areas beyond national borders.

After years of negotiations, the High Seas Treaty was finalised and opened for ratification in 2023. On 19 September 2025, the treaty reached a major milestone: it was ratified by 60 states - the threshold required for it to enter into force. As a result, the treaty will become legally binding from 17 January 2026.

This is a landmark achievement. The speed at which the treaty was negotiated, signed, and ratified is, in itself, a major success for the protection of marine ecosystems in areas beyond national jurisdiction. It reinforces several key principles of international environmental and conservation law, including, inter alia:

• The polluter-pays principle

• The ecosystem approach

• The precautionary and preventive principles

• The use and respect of traditional knowledge held by Indigenous Peoples and local communities

• And the reaffirmation of the Common Heritage of Humankind principle in governing the high seas

  
  

I’ve written previously about the significance of this last principle, which I believe is central to the future governance of areas beyond national jurisdiction.

But today, I want to explore a different question: What role - if any - does the High Seas Treaty give to non-State actors?

In the wake of the UN Ocean Conference in Nice (June 2025), some environmental groups and non-State actors have not only celebrated the treaty's ratification for its conservation measures - but have also claimed it allows non-State actors to directly enforce its provisions.

So… is that true? What power, if any, does the treaty give to individuals, NGOs, or activist groups when it comes to enforcement on the high seas?

Vigilantism vs Direct Enforcement

 The idea that private individuals or groups can take the law into their own hands isn’t new. Across disciplines, this phenomenon – often labelled vigilantism – has been widely discussed. It generally refers to efforts to prevent, investigate, or punish what are perceived as crimes, all without official legal authority.

In international law, however, this idea has taken on a new dimension. Commonly referred to as “direct enforcement”, it has emerged most clearly in the field of maritime environmental protection. Faced with alack of meaningful action from states to uphold their commitments under international law, some non-state actors have stepped in to fill the perceived gap. These organisations have attempted to enforce environmental and conservation norms themselves – with mixed results.

On one hand, some interventions have been remarkably effective, especially in protecting marine biodiversity. For example, Sea Shepherd’s direct-action campaigns helped force Japan to end its whaling seasons early and miss its quotas – at a time when Japan was illegally whaling in the Southern Ocean, in violation of the International Whaling Commission’s moratorium. On the other, such actions have sometimes crossed legal lines – or been perceived to – leading to serious consequences, including cases of piracy.

The key distinction between vigilantism and direct enforcement lies in how each justifies its actions. While vigilantism generally operates outside the law, proponents of direct enforcement actively aim to ground their interventions in legal authority. They argue that certain international treaties empower them – at least implicitly – to act as de facto enforcement agents.

I have previously examined one version of this argument: the claim that the World Charter for Nature authorises environmental activists to enforce international environmental law. In that analysis, I concluded that this interpretation was mistaken – a conclusion supported by case law in both the United States and Canada.

We’re now starting to see new claims grounded in the recently ratified High Seas Treaty – but what do those actually amount to?

What does the High Seas Treaty say?

When I first came across Paul Watson’s claim that “The High Seas Treaty (…) gives legal justification, along with the U.N. World Charter for Nature, for NGOs to intervene against activities threatening life (…)”, I was genuinely surprised.

A closer reading of the High Seas Treaty – particularly its Implementation and Compliance section – reveals a very different picture. The legal framework is relatively clear: there is no provision granting enforcement powers to non-state actors. Article 53 explicitly places responsibility for implementation on states, requiring them to take the necessary measures to uphold the agreement. Monitoring is also entrusted to states, with an added layer of oversight from the Conference of the Parties. The newly established ‘Implementation and Compliance Committee’ similarly operates within an intergovernmental framework and offers no authority – explicit or implicit – to NGOs or private actors.

In fact, there is nothing in the text of the Treaty that addresses non-state actors in an enforcement role. Their role is largely confined to knowledge sharing, capacity building, and scientific cooperation. This is very different from the World Charter for Nature, which, while legally ambiguous, at least contained language that could be interpreted as addressing non-state actors directly. That ambiguity led to genuine legal debate.

The High Seas Treaty, however, leaves no such room for doubt. Its legal design does not invite – let alone support – claims of direct enforcement authority by NGOs or other non-state actors. So why, then, does this claim continue to surface in certain environmental advocacy circles?

A few possibilities come to mind:

Is it an attempt to normalise the idea through repetition – hoping that over time, the concept of NGO-led enforcement will seem less radical and more acceptable?

Is it a strategic ambiguity aimed at influencing public opinion – or even judicial interpretation – by introducing just enough confusion to cast doubt?

Or is it simply wishful thinking driven by frustration at state inaction?

To be clear, I don’t believe these strategies are malicious. But I do find them unconvincing.

If we want serious actors – legal scholars, policymakers, and international bodies – to engage with the idea that some limited form of non-state enforcement might be justified in the context of chronic state inaction, we have to begin from a place of intellectual honesty.

That conversation has merit. But it won’t be advanced by misrepresenting the law or stretching texts beyond what they can reasonably support. If anything, such overreach risks undermining the very legitimacy of the argument.

Further Reading:

Agreement under the United Nations Convention on the Law of the Sea on the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction, 2023

Captain Paul Watson Foundation Podcast, ‘E49 – Catching Up with Captain Paul Watson’ (Spotify, 2025) <https://open.spotify.com/episode/6zbUnLsoELBM4DVI6GUuDr?si=WVOIbvL3SDyS6yIOinLU-Q>

Captain Paul Watson Foundation, ‘High Seas Treaty Ratified’ (CPWF, 2025) <https://www.facebook.com/story.php?story_fbid=1344871070334505&id=100044348739954&rdid=sGCpC9HGNE7jJb77#>

Laurence Atkin-Teillet, ‘Non-state actors’ direct enforcement of international environmental law: the example of ‘environmental pirates’’ (2024) Environmental Liability

Laurence Atkin-Teillet, ‘Redefining Piracy as Harm to the Commons’ (Rights and Justice Blog, 2025) <https://helenhall5.wixsite.com/nls-rights-and-justi/post/redefining-piracy-as-harm-to-the-commons>

Mette Eilstrup-Sangiovanni and Jason C. Sharman, Vigilantes beyond Borders: NGOs as Enforcers of International Law (Princeton University Press, 2022)