DUBAI, July 3 -- The Strait of Hormuz has two transit regimes now. One is the corridor Iran's Revolutionary Guard controls, where ships submit documentation, accept IRGC-escorted passage through a designated route, and pay a fee that two shipping companies have already settled in yuan. The other runs through Omani waters, backed by the US Navy, where vessels cross without Iranian clearance but navigate alongside a waterway where mines have not been formally cleared.

Iran suspended the fees for 60 days under the memorandum of understanding signed with the United States on June 17. The window closes around August 16. Iran's negotiators have been explicit that fees resume after it.

The July 9 nuclear working group between US and Iranian te...