A new flashpoint has emerged around the Strait of Hormuz after Donald Trump announced a 20% fee on commercial cargo passing through the strategically vital waterway. The UN’s International Maritime Organization (IMO) made clear it opposes any charge for passage through international shipping straits, while oil markets reacted with rising prices amid fears of fresh disruption to the global energy system.
The IMO said it was awaiting further details on the US announcement but reiterated its long-standing position that mandatory fees cannot be imposed for ships transiting international waterways.
An organization spokesperson said there is no legal basis for compulsory tolls or fees simply for passing through an international strait. The statement comes at a critical moment, since before the crisis escalated, roughly a fifth of the world’s seaborne oil and liquefied natural gas passed through the strait.
The US Terms
Trump announced that the US is reinstating its naval blockade of Iranian vessels in the strait, while insisting the waterway will stay open to all other commercial shipping. Writing on Truth Social, he said the Strait of Hormuz is open and will stay open, with or without Iran. He said the US is now taking on the role of “Guardian of the Strait of Hormuz” and would impose a fee equal to 20% of the value of each commercial cargo passing through, with proceeds meant to cover the cost of military operations and shipping protection in one of the world’s most unstable regions. The move has raised serious questions about the legal basis for such a unilateral charge on an international waterway.
The crisis has had an immediate impact on energy markets: Brent crude rose more than 4% to $79.25 a barrel, while US crude WTI posted a similar gain to $74.47 a barrel. Investors fear a prolonged crisis could restrict the flow of oil from Gulf producers to international markets, since the strait is the main export route for major energy producers including Saudi Arabia, the UAE, Kuwait and Qatar. Rising fuel prices are also politically sensitive for the White House, given their direct effect on American households.
The Iranian Response
Tehran maintains it still controls the strait and accuses the US of military escalation in the region; Iran’s Revolutionary Guards warned that continued American operations could have more serious consequences for the global energy sector. Iranian Foreign Ministry spokesperson Esmail Baghaei said Tehran is seeking to set up a joint mechanism with Oman to manage traffic through the strait, and Iran has also proposed its own system of permits and fees for vessels using the waterway, a position that conflicts with the IMO’s free-navigation framework.
US officials reject Iran’s claims of control, saying shipping continues and that roughly 20 vessels passed through the strait in the last 24 hours under American escort. However, ship-tracking data shows commercial traffic remains limited: according to MarineTraffic, transits through the strait fell by about 52% between July 10-12 compared with the previous week.
The Joint Maritime Information Center has urged ship crews to exercise extreme vigilance, noting that the security situation remains highly fragile.
The standoff extends well beyond a regional dispute: the US effort to tie shipping security to a financial charge on cargo, Iran’s response, and the IMO’s position together open a new front over who has the right to control international sea lanes, with real stakes for global energy prices, shipping costs and supply chains.
