The Strait of Hormuz is a strait used for international navigation overlapping with the territorial waters of Iran and Oman. Under the United Nations Convention on the Law of the Sea, such straits are subject to the right of transit passage — a legal regime that grants all ships and aircraft the right to continuous and expeditious transit, and that limits the ability of coastal states to interfere with that transit. Iran has not ratified UNCLOS. It does not accept the transit passage framework. This legal disagreement is not merely academic. It is the normative foundation on which Iran’s claimed right to close or restrict the strait rests, and the normative foundation that every other party invokes to deny Iran that right.