Strait of Hormuz: Why the US and Iran are sailing in very different legal waters

The United States and Iran hold fundamentally different legal interpretations regarding navigation through the Strait of Hormuz, a critical choke point through which 20% of the world's oil passes. Washington views it as an international waterway requiring "transit passage" under UNCLOS, while Tehran considers it part of its territorial waters, allowing only "innocent passage" under older international laws. This disagreement means Iran's toll-charging of ships is seen as illegal by the U.S., and U.S. President Donald Trump’s blockade of the passage is deemed a "grave violation" of sovereignty by Iran. Neither the U.S. nor Iran has ratified the United Nations Convention on the Law of the Sea (UNCLOS), which 171 countries have ratified, preventing it from serving as a basis for agreement. Iran further argues it is a "persistent objector" to any customary international law requiring transit passage, complicating future maritime interactions in the Strait.