India, April 10 -- As tensions rise around the Strait of Hormuz, a critical legal question has entered global debate: can a country charge ships simply to pass through an international strait?

Iran's reported proposal to impose transit fees on vessels using the Strait of Hormuz has sparked alarm across global shipping and diplomatic circles. Some have pointed to the Suez Canal as an example, arguing that transit charges are already common in maritime trade. But that comparison, while tempting, ignores a crucial legal difference.

The Suez Canal charges fees legally because it is a man-made waterway. The Strait of Hormuz, by contrast, is a natural international passage and, under established maritime law, charging tolls for mere passage t...