The United States issued a new advisory on Monday for commercial vessels transiting the Strait of Hormuz and the Gulf of Oman, recommending that U.S.-flagged ships remain as far as possible from Iran’s territorial sea without compromising navigational safety. For eastbound transits in the Strait of Hormuz, the guidance recommends routing close to Oman’s territorial waters.
The U.S. Department of Transportation’s Maritime Administration (MARAD) said the update reflects a continuing pattern of Iranian boardings and seizures. MARAD noted Iranian forces have used small boats and helicopters during boarding operations and have attempted to force commercial vessels into Iranian territorial waters, including as recently as 3 February.
The advisory recommends that U.S.-flagged commercial vessels keep AIS transponders on unless specifically directed otherwise by NAVCENT NCAGS, citing disclosures that some seizures were claimed to be linked to vessels not transmitting on AIS. It also urges pre-voyage risk assessments, inclusion of protective measures in vessel security plans, caution, and monitoring VHF Channel 16.
In the event of an incident, ships are advised to activate the Ship Security Alert System and contact the U.S. Fifth Fleet Battle Watch and the United Kingdom Maritime Trade Office (UKMTO).
On boarding risk, MARAD recommended crews not forcibly resist if Iranian forces board a U.S.-flagged commercial vessel, while stating that refraining from resistance does not imply consent. If Iranian forces seek to board, the guidance says the vessel’s master should—if ship and crew safety would not be compromised—decline permission and note the vessel is proceeding in accordance with international law as reflected in the Law of the Sea Convention.
The advisory supersedes and cancels U.S. Maritime Advisory 2025-009 and will remain in effect until 8 August 2026.
The warning comes as tensions remain high between Washington and Tehran over Iran’s nuclear programme. Both sides have indicated readiness to revive diplomacy, while the United States last week announced new sanctions targeting 15 entities, two individuals, and 14 vessels. The sanctions announcement came as Iran and the United States held indirect talks on Friday. After the Muscat discussions, Iran’s foreign minister Seyed Abbas Araghchi said viewpoints were conveyed and concerns expressed, calling it a good start while adding that continuation depends on consultations in each capital. He also said there was a consensus that negotiations would continue.
