Six commodity vessels transited the Strait of Hormuz on Tuesday, down from nine a day earlier and below the 10-day average of about 12, preliminary shipping data showed on Wednesday.
The figures could change as some ships typically switch off their transponders during the voyage.
Of the six vessels, five were entering and one was exiting, initial data from shiptracker Kpler showed at 0200 GMT. They included one Panamax and one intermediate tanker.
The U.S.-Israeli war on Iran intensified on Tuesday with Tehran-backed Houthis in Yemen launching strikes on several Saudi Arabian cities, further embroiling a U.S. ally in the conflict. In addition, American forces hit multiple Iranian oil tankers and Iran struck a U.S. base in Jordan.
Meanwhile, 25 commodity vessels transited the Bab el-Mandeb strait on Tuesday, another major maritime chokepoint in the Middle East, with 11 vessels entering and 14 exiting.
This compares with an average of around 27 ships going through Bab el-Mandeb over the past 10 days.
Among the vessels travelling through the strait were two Suezmax tankers, eight Aframax tankers and one Very Large Crude Carrier.
(Reporting by Emily Chow; Editing by Thomas Derpinghaus)