It is not too late for the U.S. to join UNCLOS but there are and will continue to be real costs for delaying accession
[Question] Will there ever reach a point where the United States will have missed so many opportunities to participate in dispute resolutions, or negotiations pursuant to the Convention, that it will no longer will have an interest in joining? Ambassador Balton responded that delay does not mean it is somehow too late to join UNCLOS, but that it has real negative consequences. Even if the United States joined UNCLOS today, it would be some time before the Commission on the Limits of the Continental Shelf would make recommendations about the U.S. continental shelf.
U.S. failure to ratify UNCLOS has damaged U.S. national security and economic growth by forclosing valuable opportunities, increasing the costs for military operations, and crippling U.S. maritime leadership as our adversaries become more aggressive.