Piracy Under International Law: UNCLOS and Universal Jurisdiction
Introduction
Piracy under international law is a narrower legal category than the word “piracy” suggests in ordinary usage. Article 101 of the United Nations Convention on the Law of the Sea (UNCLOS) covers illegal acts of violence or detention, and acts of depredation, committed for private ends by the crew or passengers of a private ship or aircraft. On the high seas, the conduct must be directed against another ship or aircraft, or against persons or property on board it. Article 101(a)(ii) separately covers such conduct against a ship, aircraft, persons, or property in a place outside the jurisdiction of any State. The definition also includes knowing voluntary participation in the operation of a pirate ship or aircraft and the incitement or intentional facilitation of piracy (UNCLOS, 1982, art. 101).
The place where the conduct occurs is part of the legal definition. Comparable violence within a State’s internal waters, archipelagic waters, or territorial sea does not constitute piracy under Article 101. The International Maritime Organization instead uses the term “armed robbery against ships” for piracy-like conduct committed within those maritime zones, under a non-binding definition adopted in Resolution A.1025(26) (IMO, 2009, para. 2.2). The exclusive economic zone is treated differently because Article 58(2) makes the high-seas provisions in Articles 88–115, including the piracy regime, applicable in the EEZ insofar as they are compatible with Part V of UNCLOS (UNCLOS, 1982, art. 58(2)).
Piracy is closely associated with universal jurisdiction, but the term can obscure the distinction between enforcement authority and criminal adjudication. Article 92 establishes exclusive flag-State jurisdiction on the high seas as the general rule, subject to exceptions expressly recognized in UNCLOS and other treaties. Within the piracy regime, Article 100 requires States to cooperate to the fullest possible extent in repression; Article 110 permits a right of visit where there are reasonable grounds for suspecting piracy; and Article 105, read together with Article 58(2), authorizes States to seize pirate ships or aircraft in the relevant maritime areas, arrest persons on board, and seize property. The courts of the seizing State may decide upon penalties and determine the treatment of seized vessels and property, subject to the rights of third parties acting in good faith (UNCLOS, 1982, arts 92, 100, 105, 110).
These rules do not make every violent incident at sea legally equivalent. The meaning of “private ends,” the requirement of “another ship” in Article 101(a)(i), the status of pirate vessels, the distinction between piracy and armed robbery against ships, and the relationship between seizure and prosecution each raise separate legal questions. Articles 100–107 and 110 provide the central treaty framework, while domestic criminal law, customary international law, judicial interpretation, and State practice remain relevant where UNCLOS leaves questions of implementation or interpretation unresolved.
1. Piracy Under International Law: The Article 101 Test
Article 101 of the United Nations Convention on the Law of the Sea provides the central treaty definition of piracy. It does not classify every unlawful act committed at sea as piracy. Article 101(a) covers illegal acts of violence or detention, or acts of depredation, committed for private ends by the crew or passengers of a private ship or private aircraft. On the high seas, the conduct must be directed against another ship or aircraft, or against persons or property on board it. Article 101(a)(ii) separately addresses conduct against a ship, aircraft, persons, or property in a place outside the jurisdiction of any State (UNCLOS, 1982, art. 101(a)).
The definition extends beyond the persons who physically carry out an attack. Article 101(b) includes voluntary participation in the operation of a ship or aircraft with knowledge of the facts that make it a pirate ship or aircraft. Both participation and knowledge are required by the text. Presence aboard a vessel does not, by itself, establish the voluntary and knowing participation contemplated by Article 101(b).
Article 101(c) reaches another category of involvement: acts that incite or intentionally facilitate conduct described in Article 101(a) or (b). The provision expressly requires intentional facilitation, distinguishing it from inadvertent assistance or association unaccompanied by the requisite intent. This allows the piracy definition to extend beyond the immediate attackers without dispensing with an individual basis for responsibility (UNCLOS, 1982, art. 101(c)).
These elements make piracy a specific legal classification rather than a general synonym for maritime crime. An assault aboard a vessel, robbery in port, internal hijacking, or politically motivated interference with shipping may constitute a serious offense without satisfying Article 101. The legal characterization depends on the requirements of the Convention, including the nature of the conduct, the actors involved, the purpose of the acts, their location, and, for high-seas piracy under Article 101(a)(i), the relationship between the attacking and victim vessels.
Article 102 qualifies the ordinary requirement that the piratical acts described in Article 101 be committed by the crew or passengers of a private ship or aircraft. Acts committed by a warship, government ship, or government aircraft whose crew has mutinied and taken control are assimilated to acts committed by a private vessel when they otherwise satisfy Article 101. The provision does not characterize ordinary conduct by State naval or government vessels as piracy; its application depends on the exceptional circumstance of a crew having mutinied and assumed control (UNCLOS, 1982, art. 102).
2. The High Seas Limit and Maritime Zones
Geographic location forms part of the law’s definition of piracy. Article 101(a)(i) addresses acts committed on the high seas, while Article 101(a)(ii) covers acts committed in a place outside the jurisdiction of any State. The location of the conduct is consequently not a jurisdictional question considered only after piracy has been established. It helps determine whether the conduct qualifies as piracy under the Convention at all.
Part VII of UNCLOS applies to areas of the sea not included in a State’s exclusive economic zone, territorial sea, internal waters, or the archipelagic waters of an archipelagic State. On the high seas, ships are generally subject to the exclusive jurisdiction of their flag State, except in cases expressly provided for in UNCLOS or other international treaties (UNCLOS, 1982, arts 86, 92). The powers granted against piracy constitute one of the principal exceptions to that general rule.
The exclusive economic zone occupies a distinct legal position. A coastal State has sovereign rights over natural resources and specified jurisdiction in the EEZ, but it does not exercise sovereignty over the zone equivalent to sovereignty over the territorial sea. Article 58(2) makes Articles 88–115 of UNCLOS applicable in the EEZ insofar as they are not incompatible with Part V. Because those provisions include the rules governing piracy, the Convention’s counter-piracy regime also operates in the EEZ despite Article 101(a)(i)’s express reference to the high seas (UNCLOS, 1982, arts 56, 58(2)).
Internal waters, the territorial sea, and archipelagic waters rest on a different jurisdictional foundation. Coastal-State sovereignty extends to internal waters and the territorial sea, while an archipelagic State exercises sovereignty over its archipelagic waters, subject in each case to the navigation rights and other limitations recognized by international law (UNCLOS, 1982, arts 2, 49). Piracy-like conduct in those waters does not become piracy under Article 101 merely because identical conduct farther seaward might satisfy the Convention’s definition.
The geography of piracy also helps explain its exceptional enforcement regime. On the high seas and, through Article 58(2), in the EEZ, international law permits specified departures from exclusive flag-State jurisdiction in response to piracy. Within waters under territorial sovereignty, comparable criminal conduct remains primarily subject to the jurisdictional framework of the coastal or archipelagic State. The distinction reflects the different allocation of authority across maritime zones rather than any difference in the seriousness of the underlying violence.
3. Private Ends and the “Another Ship” Requirement
The requirement that piracy be committed “for private ends” is one of the most debated elements of Article 101. UNCLOS does not define the phrase, and two broad approaches appear in the literature and judicial practice. A narrower interpretation treats genuinely political or ideological objectives as capable of placing conduct outside the category of private ends. A broader interpretation understands “private” principally in opposition to public or State-authorized conduct, so that political, moral, or ideological motivation does not necessarily prevent non-State violence from constituting piracy (Geiss and Petrig, 2011; Petrig, 2015).
National judicial decisions illustrate the broader approach, although they do not settle the treaty’s meaning for all States. In Castle John and Nederlandse Stichting Sirius v NV Mabeco and NV Parfin, the Belgian Court of Cassation considered violent environmental activism under Article 15 of the 1958 Convention on the High Seas, whose piracy definition closely corresponds to Article 101 of UNCLOS. The court treated the activists’ conduct as having been committed for private ends despite their stated objective of drawing public attention to marine pollution (Belgian Court of Cassation, 1986).
The United States Court of Appeals for the Ninth Circuit adopted a similarly broad interpretation in Institute of Cetacean Research v Sea Shepherd Conservation Society. In its amended 2013 opinion, the court rejected the view that “private ends” were confined to financial enrichment and concluded that personal, moral, or philosophical objectives could fall within the expression (Institute of Cetacean Research v Sea Shepherd Conservation Society, 725 F.3d 940 (9th Cir. 2013)). The decision relied on the closely related piracy definitions in UNCLOS and the 1958 High Seas Convention.
Neither judgment is an international adjudication binding States generally in the interpretation of Article 101. They nevertheless demonstrate why political or ideological motivation cannot simply be assumed to exclude piracy. The scope of “private ends” remains an interpretive question on which treaty text, drafting history, national case law, and academic commentary have not produced a universally accepted formula.
A separate issue arises from Article 101(a)(i), which requires high-seas piracy to be directed against “another ship or aircraft,” or against persons or property on board such a ship or aircraft. The word “another” provides the textual basis for the conventional two-ship requirement: the perpetrators act from one vessel against a different vessel. Violence or seizure carried out entirely by persons already aboard the victim ship does not fit that formulation.
The 1985 seizure of the Achille Lauro demonstrates the practical importance of this limitation. Members of the Palestine Liberation Front who were already aboard the cruise ship took control of it and held passengers and crew hostage. Because the seizure was internal to the vessel rather than an attack from one ship against another, it exposed a gap between the conventional piracy definition and serious violence against maritime navigation (Halberstam, 1988). The 1988 Convention for the Suppression of Unlawful Acts against the Safety of Maritime Navigation addressed conduct of this kind through a separate treaty framework. Article 3 defines specified unlawful and intentional acts against ships as offenses, including seizure of a ship by force, threat, or intimidation, without reproducing UNCLOS’s two-ship formulation (SUA Convention, 1988, art. 3).
The two-ship requirement is not expressed identically throughout Article 101. Article 101(a)(ii), governing conduct in a place outside the jurisdiction of any State, refers to acts directed against “a ship, aircraft, persons or property” rather than “another” ship or aircraft. That textual difference has led commentators to consider whether internal seizure could fall within Article 101(a)(ii) in the unusual circumstances in which a vessel is located in such a place (Petrig, 2015). The two-ship rule is consequently most precise when stated as a requirement of high-seas piracy under Article 101(a)(i), not as an unqualified condition applicable to every part of Article 101.
4. Piracy and Armed Robbery Against Ships
Many maritime attacks commonly described as piracy do not satisfy Article 101. Similar acts committed within a State’s internal waters, archipelagic waters, or territorial sea fall outside the geographic scope of the UNCLOS piracy definition. International maritime practice commonly describes such conduct as “armed robbery against ships,” preserving an important distinction between offenses within waters under State sovereignty and piracy governed by the high-seas regime.
The International Maritime Organization defines armed robbery against ships as illegal acts of violence or detention, acts of depredation, or threats of such acts, other than piracy, committed for private ends against a ship or against persons or property on board it within a State’s internal waters, archipelagic waters, or territorial sea. The definition also covers incitement or intentional facilitation of such conduct (IMO Resolution A.1025(26), 2009, para. 2.2). It appears in an IMO Assembly resolution rather than in a treaty and does not itself create a universally applicable criminal offense or an independent basis for universal enforcement jurisdiction.
The jurisdictional consequences differ accordingly. In internal waters and the territorial sea, coastal-State sovereignty supplies the basic jurisdictional framework, although the exercise of criminal jurisdiction aboard foreign ships passing through the territorial sea is subject to the specific rules in Article 27 of UNCLOS. Archipelagic waters are likewise subject to the sovereignty of the archipelagic State, qualified by applicable navigation regimes and other international obligations. A foreign State cannot invoke Article 105 merely because an attack inside those waters resembles piracy.
Foreign enforcement action within another State’s sovereign maritime zones requires an independent legal basis. Depending on the circumstances, that basis may arise from the coastal State’s consent, an applicable treaty, or a binding Security Council decision adopted within the powers conferred by the United Nations Charter. The exceptional universal enforcement authority associated with piracy cannot be transferred to territorial-water offenses by terminology alone.
The distinction is legal rather than descriptive. A violent boarding, kidnapping, or theft can present the same danger to a ship and its crew on either side of the territorial-sea limit, yet international law allocates enforcement authority differently according to the maritime zone in which the conduct occurs. Calling an incident “piracy” in political statements or news reporting does not bring it within Articles 100–107 of UNCLOS. Its legal classification depends on the elements prescribed by the applicable international rules and on the jurisdictional status of the waters where the incident takes place.
5. Pirate Ships, Participation, and Facilitation
Article 103 of UNCLOS defines a pirate ship or aircraft by reference to its intended or completed use and the persons exercising dominant control over it. A vessel is considered piratical when those in dominant control intend to use it to commit an act referred to in Article 101. The definition also covers a vessel already used to commit such an act while it remains under the control of the persons responsible (UNCLOS, 1982, art. 103).
Pirate status does not arise merely because a vessel has carried a person who intends to commit piracy or because it has some past connection with piratical activity. Article 103 requires the relevant intention of those in dominant control or, following a completed act, continuing control by the persons responsible. The provision thus links the legal character of the vessel to both its use and the authority exercised aboard it.
Article 101(b) connects the status of the vessel with individual responsibility. Voluntary participation in the operation of a pirate ship or aircraft constitutes piracy only where the participant knows the facts that make the vessel piratical. Physical presence alone does not establish the voluntary and knowing participation required by the Convention. Article 101(c) separately covers incitement and intentional facilitation of acts falling within Article 101(a) or (b) (UNCLOS, 1982, art. 101(b)–(c)).
A pirate ship does not automatically become stateless. Article 104 expressly provides that a pirate ship or aircraft may retain its nationality and that retention or loss is determined by the law of the State from which the nationality was derived (UNCLOS, 1982, art. 104). Piracy and statelessness are consequently distinct legal conditions. The universal powers recognized in relation to piracy cannot be explained simply by assuming that a pirate vessel has lost its nationality.
6. Universal Jurisdiction and Its Legal Basis
Piracy is the classic example of universal jurisdiction in international law. Universal criminal jurisdiction permits a State, within the limits recognized by international law and its own legal system, to exercise jurisdiction without relying on the ordinary territorial or nationality connections between the forum, the offender, and the offense. Piracy occupied this exceptional position long before the adoption of UNCLOS, and the 1958 Convention on the High Seas already contained a treaty regime for its repression.
A leading explanation for this exceptional jurisdiction lies in the traditional location of piracy. The offense occurs in maritime areas outside the territorial sovereignty of any State, where exclusive reliance on territorial jurisdiction would leave no coastal sovereign with the ordinary basis for enforcement. The common interest in protecting navigation and commerce on the high seas reinforced this jurisdictional response. The gravity of piracy alone does not adequately explain the rule, since many serious offenses have not historically attracted universal jurisdiction on that basis (Petrig, 2015).
The concept becomes clearer when prescriptive, adjudicative, and enforcement jurisdiction are separated. Prescriptive jurisdiction concerns a State’s authority to subject conduct to its criminal law. Adjudicative jurisdiction concerns the competence of its courts to determine a criminal case. Enforcement jurisdiction concerns coercive action, including boarding, seizure, arrest, and detention. International law does not necessarily confer each form of jurisdiction to the same extent or on identical conditions.
UNCLOS is particularly explicit about enforcement authority. Article 105 provides that every State may seize a pirate ship or aircraft on the high seas or in another place outside the jurisdiction of any State, arrest persons aboard, and seize property. Through Article 58(2), the relevant piracy provisions also apply in the exclusive economic zone insofar as they are compatible with Part V of the Convention (UNCLOS, 1982, arts 58(2), 105).
The second sentence of Article 105 states that the courts of the State carrying out the seizure may decide upon the penalties to be imposed. Its relationship with universal adjudicative jurisdiction has attracted differing interpretations. Customary international law is widely understood to recognize universal criminal jurisdiction over piracy, while Article 105 expressly confirms the competence of the seizing State’s courts. Debate remains over whether the treaty provision independently supplies the full basis for universal adjudicative jurisdiction or principally regulates the position of the State that has effected the seizure (Petrig, 2015).
International judicial discussion illustrates the need for this distinction. In Arrest Warrant of 11 April 2000, the International Court of Justice did not decide the general legality or scope of universal jurisdiction. President Guillaume discussed piracy as an established instance of universal jurisdiction in a separate opinion, while Judges Higgins, Kooijmans and Buergenthal addressed piracy in their joint separate opinion (ICJ, 2002). These observations are influential contributions to the doctrine, but they are not holdings of the Court.
7. Visit, Seizure, Arrest, and Article 105
Universal jurisdiction over piracy does not create an unrestricted power to stop foreign vessels at sea. Article 110 establishes a right of visit where there are reasonable grounds for suspecting that a foreign ship is engaged in piracy. The provision applies principally to warships and, through Article 110(5), mutatis mutandis to military aircraft and other duly authorized government ships or aircraft that are clearly marked and identifiable as such. Article 58(2) extends the relevant rule to the exclusive economic zone, subject to compatibility with Part V (UNCLOS, 1982, arts 58(2), 110).
A visit under Article 110 is initially investigative. The warship may send a boat under the command of an officer to verify the vessel’s right to fly its flag. If suspicion remains after the documents have been examined, a further examination may be conducted aboard the ship with all possible consideration. Where the suspicions prove unfounded and the boarded vessel has committed no act justifying them, the vessel must be compensated for resulting loss or damage (UNCLOS, 1982, art. 110(2)–(3)).
Article 105 provides the more intrusive power of seizure. It permits every State to seize a pirate ship or aircraft, or a ship or aircraft taken by piracy and under pirate control, and to arrest persons and seize property aboard. Article 106 nevertheless recognizes that a seizure may be effected on suspicion of piracy and imposes State responsibility where that seizure occurred without adequate grounds. UNCLOS does not define a precise evidentiary threshold for “adequate grounds,” but the reasonable suspicion sufficient to initiate an Article 110 visit cannot simply be equated with a conclusive determination that the conditions for seizure have been satisfied (UNCLOS, 1982, arts 105–106).
Only specified State vessels may carry out a seizure on account of piracy. Article 107 restricts that authority to warships, military aircraft, and other ships or aircraft clearly marked and identifiable as being on government service and authorized for that purpose (UNCLOS, 1982, art. 107). A private merchant ship that resists an ongoing pirate attack does not acquire the public enforcement authority conferred by Article 105 merely because its crew acts lawfully in defense of the vessel.
UNCLOS does not provide a complete code governing force during counter-piracy enforcement. In M/V Saiga (No. 2), a case that did not concern piracy, the International Tribunal for the Law of the Sea stated the broader law-enforcement principle that force in arresting a ship should be avoided as far as possible and, where unavoidable, must not exceed what is reasonable and necessary in the circumstances (M/V Saiga (No. 2), 1999, paras 155–156). The use of naval forces in an ordinary counter-piracy operation does not by itself make international humanitarian law applicable; the existence of an armed conflict and the relevant connection to that conflict remain necessary for the rules governing armed conflict to apply.
8. Prosecution After Seizure
Seizure and criminal prosecution are separate stages of the legal process. Article 105 authorizes the courts of the seizing State to decide upon the penalties to be imposed, but UNCLOS does not prescribe a uniform criminal code for piracy. It does not establish identical national offense definitions, evidentiary rules, trial procedures, sentencing rules, or penalties for all States (UNCLOS, 1982, art. 105).
Domestic law consequently remains central to prosecution. States differ in the manner in which piracy is criminalized and in the jurisdictional provisions through which their courts give effect to international law. A State may have authority under international law to act against piracy while still encountering difficulties under its own legislation if the offense, jurisdictional basis, or relevant criminal procedure has not been adequately established. Counter-piracy operations off Somalia exposed this practical divide between international enforcement authority and national capacity or willingness to prosecute (United Nations, 2011, S/2011/30; Petrig, 2015).
Article 100 does not convert the duty of cooperation into an automatic duty to prosecute every person seized. It requires all States to cooperate to the fullest possible extent in repressing piracy on the high seas or in any other place outside the jurisdiction of any State. Article 105, by contrast, provides that the courts of the seizing State “may” decide upon penalties. The better interpretation is that Articles 100 and 105 do not, by themselves, establish a general obligation either to prosecute every piracy suspect or to extradite that person (UNCLOS, 1982, arts 100, 105; Petrig, 2015).
A different treaty may impose more specific duties when the conduct falls within its scope. Under the 1988 Convention for the Suppression of Unlawful Acts against the Safety of Maritime Navigation, a State Party in whose territory an alleged offender is present must, if it does not extradite that person, submit the case without delay to its competent authorities for the purpose of prosecution. Those authorities then proceed according to the law of that State in the same manner as in other offenses of a serious nature (SUA Convention, 1988, art. 10). The obligation is to submit the case to the competent authorities, not to guarantee prosecution or conviction irrespective of national legal requirements.
The SUA Convention complements rather than enlarges Article 101. It covers specified unlawful acts against maritime navigation, including seizure of a ship by force or threat and certain acts of violence against persons aboard. Conduct may consequently fall within SUA even when it does not satisfy the location, private-ends, or two-ship elements associated with piracy under UNCLOS. Transfer to another prosecuting State may also be possible, subject to a lawful jurisdictional basis and applicable rules governing custody, surrender, non-refoulement, and fair trial. Universal jurisdiction does not eliminate those separate legal questions.
9. Somalia and Exceptional Territorial Enforcement
The campaign against piracy off Somalia exposed the geographic limits of the ordinary UNCLOS regime. Articles 100–107 provide extensive powers in relation to piracy on the high seas and, through Article 58(2), in the exclusive economic zone. They do not create a general right for foreign naval forces to enter another State’s territorial sea to exercise equivalent counter-piracy powers.
Security Council Resolution 1816 (2008) supplied an exceptional legal basis for such action in Somalia. Acting under Chapter VII of the United Nations Charter and following the consent of Somalia’s Transitional Federal Government, the Council authorized cooperating States for a limited period to enter Somali territorial waters to repress piracy and armed robbery at sea and to use measures consistent with those available against piracy on the high seas (UNSC Resolution 1816, 2008). Resolution 1846 extended that arrangement, while Resolution 1851 authorized cooperating States and regional organizations, subject to the conditions imposed by the Council, to undertake appropriate necessary measures in Somalia for the suppression of piracy and armed robbery (UNSC Resolutions 1846 and 1851, 2008).
The Council expressly guarded against treating those authorizations as a general alteration of the law of the sea. The resolutions stated that the measures applied only to the situation in Somalia, did not affect the rights and obligations of States under international law in other situations, and were not to be regarded as establishing customary international law. The exceptional regime consequently depended on the specific Security Council decisions and Somali consent rather than on an expanded interpretation of Article 101.
The piracy-specific authorization was renewed repeatedly, most recently for three months by Resolution 2608 of 3 December 2021. In a letter dated 26 February 2022, Somalia informed the President of the Security Council that it would no longer request renewal, stating that the authorization had achieved its intended objective (Somalia, 2022, S/2022/162). The authorization consequently expired on 3 March 2022.
That expiry did not terminate every Security Council-authorized maritime interdiction in Somali territorial waters. A separate sanctions regime, originating in measures directed at prohibited charcoal, arms, military equipment, and improvised explosive device components, continues to authorize specified maritime interdiction measures. Resolution 2806 (2025) renewed that regime until 30 November 2026 (UNSC Resolution 2806, 2025). Its legal basis, objects, and conditions are distinct from the former counter-piracy authorization and should not be treated as a continuation of it.
10. Current ILC Work and Unresolved Questions
Piracy and armed robbery at sea have also returned to the active agenda of the International Law Commission. In 2019, the Commission placed “Prevention and repression of piracy and armed robbery at sea” in its long-term program of work. It added the topic to its active program in 2022 and appointed Yacouba Cissé as Special Rapporteur (International Law Commission, 2019; 2022).
The Commission considered Cissé’s first report, A/CN.4/758, in 2023. Following plenary debate and work in the Drafting Committee, it provisionally adopted draft articles 1 to 3, together with commentaries. Those provisions address the scope of the project and the definitions of piracy and armed robbery at sea (International Law Commission, 2023).
Work continued in 2024 on the basis of the second report, A/CN.4/770, and a Secretariat memorandum, A/CN.4/767, concerning the development of the relevant definitions and academic writings. The Commission referred proposed draft articles 4 to 7 to the Drafting Committee. The Committee provisionally adopted draft article 4 and presented an interim report for information. After Cissé resigned as Special Rapporteur, the Commission appointed Louis Savadogo on 2 August 2024 (International Law Commission, 2024).
At the Commission’s seventy-seventh session in 2026, Savadogo presented his first report, A/CN.4/791 and Corr.1. It examined legal instruments on cooperation, national policing measures, State practice, and mechanisms for criminal prosecution, and proposed eighteen draft articles. Following plenary consideration, the Commission referred proposed draft articles 5 to 14 to the Drafting Committee (International Law Commission, 2026).
The Drafting Committee subsequently provisionally adopted draft articles 3 bis, 4 bis, 5, 5 bis, 5 ter and 5 quater. The Commission took note of the Chair of the Drafting Committee’s interim report for information. These procedural steps do not place the provisions on the same footing as draft articles formally adopted by the Commission, nor do they give them binding legal effect (International Law Commission, 2026).
The project remains a work in progress. Neither the reports of the Special Rapporteurs nor draft provisions considered or provisionally adopted within the Commission amend UNCLOS or bind States merely by virtue of their consideration by the ILC. Nor does inclusion of a proposition in a draft article, without more, establish that it reflects customary international law. Its eventual legal significance will depend on the Commission’s final treatment, the character of the proposed rule, supporting State practice and opinio juris where custom is claimed, and the response of States to any completed outcome.
The continuing work nevertheless demonstrates sustained attention to problems that UNCLOS does not resolve in complete detail. National criminalization, jurisdiction, interstate cooperation, the legal distinction between piracy and armed robbery at sea, and the movement from maritime interception to prosecution remain areas in which treaty law interacts with domestic legislation and differing State practice. Article 101 remains the central treaty definition of piracy, while the wider regime continues to generate questions of interpretation and implementation.
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Conclusion
Piracy under international law is not a general description of robbery, hijacking, or violence at sea. It is a defined legal category governed principally by UNCLOS. Article 101 specifies the relevant conduct, private-ends requirement, actors, geographic conditions, knowing participation, incitement, and intentional facilitation. For conduct on the high seas under Article 101(a)(i), the act must also be directed against another ship or aircraft, or against persons or property aboard it.
When those requirements are met, international law permits exceptional jurisdictional powers in relation to piracy. UNCLOS allows specified departures from exclusive flag-State jurisdiction through the right of visit, seizure of pirate vessels, arrest, and seizure of property. Through Article 58(2), the relevant rules also operate in the exclusive economic zone. They do not, however, establish a general foreign enforcement power within another State’s territorial waters, where piracy-like conduct is ordinarily treated as armed robbery against ships and falls under a different jurisdictional framework.
Universal jurisdiction does not eliminate the distinction between defining piracy, exercising enforcement authority, and bringing a criminal case before a national court. Each depends on its own legal basis and conditions. The UNCLOS regime is exceptional because it permits States to act against piracy beyond the ordinary constraints of flag-State exclusivity, but those powers remain legally delimited rather than unlimited.
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United Nations Security Council (2021) Resolution 2608 (2021), S/RES/2608(2021), 3 December 2021.
United Nations Security Council (2025) Resolution 2806 (2025), S/RES/2806(2025), 12 December 2025.
United States Court of Appeals for the Ninth Circuit (2013) Institute of Cetacean Research v Sea Shepherd Conservation Society, Order and Amended Opinion, filed 25 February 2013, amended 24 May 2013, 725 F.3d 940.
