The US Maritime Administration (MARAD) said in an advisory issued on Monday that US-flagged vessels should stay away from Iran’s territorial waters, a warning that comes as the US has built up forces in the region to prepare for a potential attack on the Islamic Republic.
“It is recommended that US-flagged commercial vessels transiting these waters remain as far as possible from Iran’s territorial sea without compromising navigational safety,” MARAD said. “When transiting eastbound in the Strait of Hormuz, it is recommended that vessels transit close to Oman’s territorial sea.”
The advisory came after the US military alleged that a US-flagged ship was approached by Iranian gunboats that threatened to board the vessel in the Strait of Hormuz and that the US ship was then escorted by a US Navy guided-missile destroyer. That same day, a F-35 fighter jet from the aircraft carrier USS Abraham Lincoln shot down an Iranian drone in the Arabian Sea.
MARAD said that US-flagged commercial vessels navigating in the area should “coordinate voyage planning with U.S. Naval Forces Central Command (NAVCENT) Naval Cooperation and Guidance for Shipping (NCAGS) and consider their recommendations and guidance whenever possible.”
During the 12-day US-Israeli war against Iran in June 2025, the Iranian parliament voted to close the Strait of Hormuz as a retaliatory measure, which would have a huge impact on global oil shipping, but a ceasefire was reached a few days later. Restricting shipping in the Strait remains an option for Iran if it comes under another US or Israeli attack.
Iranian officials have repeatedly warned that if President Trump follows through on his threats to bomb Iran, Iranian missiles would target US bases in the region, and it’s unlikely that Tehran will give the US notice of its plans to attack as it did when it targeted the Al Udeid Air Base in Qatar following US airstrikes on Iranian nuclear facilities.
