https://www.usni.org/magazines/proceedings/2022/october/repairing-submarine-cables-wartime-necessity

During hostilities in contested oceans, the peacetime arrangements for repairing cables will flounder. Peacetime cable ship maintenance agreements contain force majeure clauses that excuse performance of cable ships in the event of war involving the flag state or major global powers. Even if the agreements were to be performed, the normal peacetime repair ship call-out procedures, such as the customary “first come, first serve” cable repair priority and common shared international consensus decision-making practices, would be overwhelmed in a topsy-turvy scenario in which belligerent actions damage many submarine cables and national governments all want their specified cable repairs attended to first.

Crews will be reluctant to sail in contested waters where the cable ships are likely targets. Multinational crewing with divided national loyalties and visa restrictions add complexity in wartime conditions.

Standard marine protection and indemnity insurance policies exclude wartime coverage, stating: “In the event of war or war-like conditions between any of the following states: The United Kingdom, the United States of America, France, the Russian Federation, the People’s Republic of China, the insurance against war perils shall automatically terminate.” Cable ship owners will not risk their ships without adequate and affordable war risk insurance or national guarantees to replace sunk, damaged, or captured cable ships, and indemnify them for breaking existing contracts and other damages associated with hostilities.

Not exactly the scenario being faced right now, but a reminder that as things stand, undersea cable infrastructure is vulnerable and things could get much worse in war scenarios.