Confirmed vessel crossings through the Strait of Hormuz rose to 13 on Thursday from nine a day earlier, according to MarineTraffic data released Friday.
Seven vessels entered the Gulf, while six exited.
Nine vessels traveled through the Iranian Unilateral Scheme, while none were confirmed as using the Strait of Hormuz Traffic Separation Scheme. The routes taken by four vessels remained undetermined.
The crossings included two sanctioned vessels, three vessels identified as part of a shadow fleet and eight other ships.
Traffic through the Bab al-Mandeb Strait also increased slightly, with 29 confirmed crossings, from 28 the previous day.
Eighteen vessels entered the Red Sea, while 11 exited. Two dark transits, in which vessels sailed without transmitting tracking signals, were also recorded.
Four sanctioned vessels and two shadow vessels were among those crossing Bab al-Mandeb.
MarineTraffic said no new confirmed vessel attacks were recorded.
The Strait of Hormuz, located between Iran and Oman, is a critical route for global energy shipments connecting the Gulf with the Arabian Sea.
Oil and petroleum liquids transported through the strait averaged 4.9 million barrels per day in the second quarter of 2026, sharply below 21.6 million barrels per day in the final quarter of 2025 before the regional conflict began, according to the US Energy Information Administration.
The International Maritime Organization has recorded 65 confirmed maritime incidents in the Strait of Hormuz and the wider Middle East as of Aug. 11, along with 17 seafarer fatalities.
