Argentina took its case to the tribunal in October after months of tension over the Falklands and the planned drilling. President Javier Milei has described the project as unlawful. The court can issue legally binding rulings on maritime disputes.

Sea Lion is operated by Navitas Petroleum Development and Production Ltd, a UK-based, wholly owned subsidiary of Israeli company Navitas Petroleum, alongside British partner Rockhopper Exploration. The companies reached a final investment decision earlier this year on the Sea Lion Northern Development, meaning approvals and funding for full-scale execution have been secured. Navitas says first oil is planned for March 2028.

The UK says it is participating in the process under the UN Convention on the Law of the Sea (UNCLOS). The prime minister’s official spokesman told The Independent on Monday that the government would set out its position on Argentina’s request for provisional measures before the tribunal. He said the UK would defend its interests and those of Falkland Islanders, adding that the hearing was “not about the sovereignty of the Falklands.”

In September, Prime Minister Andy Burnham said the UK would respect the islanders’ right to choose to be British and would defend that position. Falkland Islanders have previously voted overwhelmingly to remain a British Overseas Territory.

Britain has controlled the islands since 1833, while Argentina has long claimed them as part of its territory. The two countries fought a brief war over the Falklands, which Argentina calls Las Malvinas, in 1982; the sovereignty dispute has continued since.