On 13 October 2026, Argentina asked the International Tribunal for the Law of the Sea (ITLOS) in Hamburg, Germany to stop the UK from beginning oil production at the Sea Lion field, north of the Falkland Islands (Islas Malvinas). The request puts a sovereignty dispute and an oil project in front of the Tribunal together, and it touches almost every question that a law student meets in the LOS: How far a coastal State's sovereign rights extend? How far compulsory dispute settlement reaches? What a State may do while a title is contested? And, how fast a Tribunal can act?
Argentina filed under Article 290(5) of the United Nations Convention on the LOS (UNCLOS), which lets the ITLOS prescribe provisional measures until an Annex VII Arbitral Tribunal is constituted. It had started that arbitration on 28 September. The UK rejected Argentina's claims on 11 October and declined to adopt the measures that Argentina had asked for.
From 1833 to Hamburg: How the dispute evolved?
The roots are territorial. Britain took control of the Islands in 1833, an act that Argentina has protested ever since, and the two States have claimed sovereignty over the Islands, South Georgia and the South Sandwich Islands for almost two centuries. In 1982, the quarrel became a 74-day war, after which the British administration was restored.
The diplomatic track ran through the UN. In 1965, the General Assembly (GA) adopted Resolution 2065 (XX), the first to treat the Islands as a decolonisation case and to call for a peaceful solution of the sovereignty dispute between the two Governments. The Assembly and its Decolonisation Committee still treat the matter as a "special and particular" colonial situation to be ended by negotiation. The UK's consistent reply has been that there can be no dialogue on sovereignty unless the Islanders so wish.
Oil turned that old argument into a maritime one. When Britain sent the Shackleton Economic Survey in 1976, with hydrocarbons in view, Argentina protested, and a serious incident followed. The GA then adopted Resolution 31/49 on 1 December 1976 by 102 votes to one, with 32 abstentions, calling on both parties to refrain from decisions that would introduce unilateral modifications while the Islands go through the process that the Assembly had recommended.
Cooperation was tried and failed. On 27 September 1995, the two States signed a Joint Declaration on offshore activities in the South-West Atlantic. Each read it differently, it was never implemented, and the UK went on to grant exploration licences. Argentina terminated the Declaration on 27 March 2007. Exploration drilling followed in 2010 and 2011, and in April 2015, a blowout preventer failed at the Isobel Deep well, about 30 kilometres (km) from Sea Lion; Argentina publicly voiced its concern at the time.
The recent steps are short. On 21 September 2026, the Falkland Islands authorities extended the production licences for five years. Argentina began Annex VII arbitration on 28 September, the UK answered on 11 October, and the request to the ITLOS followed on 13 October.
How the LOS came to this point?
The UNCLOS was adopted in 1982, entered into force in 1994, and created the ITLOS, which began work in Hamburg in 1996. Two features of the package matter here.
First, the drafters knew about disputes over the colonial territory. Resolution III, annexed to the Final Act of the Third UN Conference, asks parties to a sovereignty dispute over a territory under colonial domination to consult, to "make every effort" to enter provisional arrangements of a practical nature, and not to jeopardise a final settlement. Argentina made declarations on the signature and ratification that Resolution III does not affect the Malvinas question and that it will treat unilateral activity without its consent as null and void. Resolution III is not part of the Convention, Argentina uses it as an aid to interpretation.
Second, Part XV gives the UNCLOS what most Treaties lack: compulsory procedures that end in binding decisions. Article 287 lets each State choose a forum (the ITLOS, the International Court of Justice [ICJ], an Annex VII or Annex VIII Tribunal). When the parties have not chosen the same one, Article 287(5) sends the dispute to Annex VII arbitration. Article 288 limits that jurisdiction to disputes about the interpretation or application of the Convention, Article 297 trims it for certain coastal State discretions, and Article 298 lets a State opt out in advance of three categories: boundary delimitation and historic titles, military activities and certain law enforcement, and disputes before the UN Security Council (SC).
What the ITLOS adds is speed. Article 290(5) lets it prescribe provisional measures while an Annex VII Tribunal is still being assembled, provided that the Tribunal would prima facie have jurisdiction and the situation is urgent.
Case law has since shaped how far this machinery reaches. The Chagos Marine Protected Area arbitration (2015) held that a Tribunal under Part XV cannot decide a dispute that is really about land sovereignty. The ICJ's 2019 Advisory Opinion on Chagos (Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965) then stressed the GA's role in decolonisation.
The field and the map
Sea Lion lies in the North Falkland (North Malvinas) Basin. Argentina's request puts it about 107 nautical miles north of the Islands and gives its area as roughly 541 square km; the operator's own materials describe the distance as about 220 km. The Sea Lion discovery area sits inside the production licence PL032, and the request also names PL004b. Navitas Petroleum is the operator with 65 per cent and Rockhopper Exploration holds 35%. An independent last year (2025) resource report put gross contingent resources at 917 million barrels, a figure to prefer over the larger numbers that some press reports quote.
The map shows licence blocks north, south-east and south of the Islands, coloured by the holder. Its legend also marks the baselines, the outer limit of the exclusive economic zone and the outer limits of the continental shelf, which is the point: the entitlement that Argentina invokes is a shelf entitlement generated by the Islands themselves.
The timetable explains the urgency. The final investment decision of 10 December 2025 moved the development area into a 35-year production phase. Drilling is scheduled for early next year (2027), and Rockhopper's mid-2026 results point to first oil in the first quarter of 2028.
What Argentina is asking for?
Argentina asks the ITLOS to prescribe four measures, pending the constitution of the Annex VII Tribunal. The UK would be required to: Prevent the commencement or continuation of the exploitation of hydrocarbons on the continental shelf in the North Malvinas Basin by the Sea Lion project; Refrain from using information obtained from exploring the disputed areas to the detriment of Argentina's rights; Cease preventing Argentina from complying with its duty under Articles 192 and 194 to protect and preserve the marine environment of the disputed areas; and Refrain from any other measure that might aggravate the dispute, in particular new permits for the exploitation of the disputed shelf.
Note what is not requested: a halt to all exploration, or a ruling on sovereignty. Argentina says that it is not asking the Arbitral Tribunal to decide who owns the Islands. It says that it is protecting its sovereign rights over the shelf under Articles 56 and 77 and its Part XII duties until that question is settled.
The legal test has three parts, and students should keep them apart. First, prima facie jurisdiction: the Annex VII Tribunal must appear to have jurisdiction over the dispute. Second, plausibility: the rights that Argentina assert must be at least plausible, and linked to the measures sought. Third, urgency and irreparable prejudice: following MOX Plant (The MOX Plant Case - Ireland v. UK, Provisional Measures, 2001, ITLOS), action prejudicial to the rights of a party, or causing serious harm to the marine environment, must be likely before the Arbitral Tribunal can act. The Annex VII Tribunal may later modify, revoke or affirm whatever the ITLOS orders.
On the third limb, Argentina argues that drilling permanently alters the seabed and subsoil and cannot be compensated in money, relying on the ITLOS's 2015 reasoning in Ghana/Côte d'Ivoire (Dispute concerning the delimitation of the maritime boundary between Ghana and Côte d'Ivoire in the Atlantic Ocean). It also points to the 2015 blowout-preventer failure and to a company oil-spill contingency plan that modelled a 30% probability of a heavy-crude blowout reaching Argentine waters within 30 days. It adds that the site is remote, in harsh seas, and that neither operator has run a producing offshore field before. These are Argentina's assertions and the UK has not accepted them.
The "mixed dispute" objection
In the Chagos Marine Protected Area arbitration (2015), a majority held that a claim framed around the "coastal State" was really about sovereignty over land, which Part XV does not cover. The Coastal State Rights tribunal (Ukraine v. Russia, 2020) and the South China Sea jurisdiction award (The South China Sea Arbitration between the Republic of the Philippines and the People’s Republic of China) (2015) applied the same approach: they proceeded only where claims could be decided without ruling on sovereignty. Argentina's statement of claim alleges a breach of its "sovereignty and sovereign rights" under Articles 2, 56 and 77. Any entitlement to the Sea Lion shelf appears to flow from the Islands. Argentina answers that it asks for protection of the rights pending settlement, not a title ruling. The UK will say that the Tribunal must look at the real issue, not the label.
Article 298(1)(a) and the reciprocity trap
If Argentina's case is really a duty to refrain from unilateral acts in a disputed shelf, it resembles the duty in Articles 74(3) and 83(3) not to jeopardise a final agreement. The UK can then call it a delimitation-type dispute. Article 298(3) also bars a State that has made a declaration from taking an excepted dispute to another party without that party's consent, so, Argentina's own 1995 Declaration is a second obstacle. Argentina replies that nothing is being delimited (its request says as much). But, that answer pushes it back toward objection one. This is the pincer.
Categories (b) and (c): marginal
Commercial drilling is not a military activity, and the law-enforcement limb applies only to fisheries and research disputes excluded by Article 297. The UK could mention SC Resolutions 502 and 505 of 1982, but the matter has since been handled by the GA's Decolonisation Committee, and Article 298(1)(c) requires the Council to be exercising its functions.
Other lines
The UK may argue that Resolutions 2065 and 31/49 are not UNCLOS obligations, and that Articles 279 and 300 cannot supply jurisdiction by themselves (the Southern Bluefin Tuna Tribunal left room only for "egregious" conduct [Southern Bluefin Tuna Cases - New Zealand v. Japan, and Australia v. Japan, Provisional Measures]). Article 283 (exchange of views) and Articles 281 and 282 look weak for the UK; the Monetary Gold principle (Monetary Gold Removed from Rome in 1943 - Italy v. France, the UK of Great Britain and Northern Ireland and the United States of America, ICJ) protects States, not companies or a territorial Government. Self-determination is not an UNCLOS right, but, the UK will use it to show that the dispute is about the territorial status. The UK has reportedly said that it will contest the jurisdiction "vigourously"; that wording appears in Argentina's request.
Argentina's best route
The marine-environment claims. In the 2016 South China Sea award, the Tribunal said that Part XII obligations apply in all maritime areas and that sovereignty questions are irrelevant to them, a passage that Argentina quotes. The 2026 Coastal State Rights award upheld environmental claims against Russia in a sovereignty-tinged setting. The weakness is Argentina's third measure, which presupposes Argentine regulatory authority over the area.
Two patterns stand out. The ITLOS often prescribes measures of its own design that bind both parties (as in Enrica Lexie Incident - Italy v. India, Provisional Measures), rather than adopting the applicant's list. And, it treats the interval before the Annex VII Tribunal is constituted as the measure of urgency. Counting from the 28 September notice, the Tribunal could be in place around December 2026 to January 2027, close to the early-2027 drilling start. That gives the UK an argument that nothing irreparable happens before the Tribunal can act.
Outlook and take-aways
An order halting Sea Lion outright looks unlikely on the record of past cases. Narrower measures are more plausible: non-aggravation, cooperation, information-sharing, and perhaps limits on new permits or new activity. The ITLOS has said that dates for the oral hearings will be announced separately. Whatever it orders, the Annex VII Tribunal can revisit the question, and a later award could still decline jurisdiction, as happened after the Southern Bluefin Tuna.
Three points are: Part XV reaches only disputes about the Convention. Sovereignty over land sits outside it, and Chagos shows that tribunals will look past the label on a claim; Optional exceptions under Article 298 and implied limits on jurisdiction are different things. The first depends on declarations and dates; the second comes from the Convention's scope.; and Provisional measures need jurisdiction, plausible rights and urgency, and urgency is measured against the time before the Annex VII Tribunal can act.
The oil is real, but the question for the Tribunal is narrower than history suggests.
The writer is an attorney-at-law and a chartered shipbroker
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The views and opinions expressed in this column are those of the writer, and do not necessarily reflect those of this publication