Vienna Conclusions on Submarine Cables and Pipelines Adopted

The International Law Association (ILA) adopted the Vienna Conclusions on Monitoring, Prevention and Response at Sea in Respect of Intentional Damage to Submarine Cables and Pipelines at its 82nd Biennial International Law Conference, held in Vienna from 17 to 21 August 2026. Prepared by the ILA Committee on Submarine Cables and Pipelines under International Law, the Vienna Conclusions comprise 23 conclusions intended to identify and clarify the existing rules of international law governing measures that States may take in relation to intentional damage to submarine cables and pipelines.

The Vienna Conclusions distinguish between monitoring activities, measures to prevent anticipated intentional damage and measures responding to damage that has occurred. The powers available to States vary according to the maritime zone concerned.

Beyond national jurisdiction, the Vienna Conclusions provide that States may conduct monitoring activities on the high seas subject to due regard for the rights of other States. Where reasonable grounds exist to suspect that a foreign vessel intends to engage, or has engaged, in intentional damage to a submarine cable or pipeline, a State may approach the vessel and request information. More intrusive measures, including boarding, remain subject to the applicable jurisdictional requirements under international law, including flag-State consent where no independent basis for enforcement jurisdiction exists.

The Vienna Conclusions also address the obligations of flag States, including the adoption of legislation contemplated by Article 113 of the United Nations Convention on the Law of the Sea and the exercise of due diligence to prevent vessels flying their flag from damaging submarine cables and pipelines. The ILA resolution commends the Vienna Conclusions and their accompanying commentary to States, international organisations, courts and tribunals, and requests their transmission to, among others, the International Court of Justice, the International Tribunal for the Law of the Sea and the Permanent Court of Arbitration.