This advisory supersedes and cancels U.S. Maritime Advisory 2026-001

1. References: None.

2. Issue: Iran continues to threaten and conduct strikes on commercial vessels transiting the Persian Gulf, Strait of Hormuz (SoH) and Gulf of Oman. Risks of Iranian attacks against commercial shipping remain high in these areas.

Prior to the commencement of combat operations in this region, Iranian forces historically utilized small boats and helicopters during boarding operations and have attempted to force commercial vessels into Iran’s territorial sea. Iranian threats to commercial vessels now additionally include direct missile attacks, armed unmanned aerial vehicles (UAVs), and armed unmanned surface vessels (USVs).

The U.S. government is continually assessing the maritime security situation in the region to identify and differentiate threats and safeguard freedom of navigation, ensure the free flow of commerce, and protect U.S. vessels, personnel, and interests.

3. Guidance:

U.S.-flagged vessels operating in these areas should maintain a minimum standoff of 30 nautical miles from U.S. military vessels to reduce the risk of being mistaken as a threat and should answer all VHF calls from coalition navies. Vessels should be aware that U.S. and other coalition naval forces may conduct maritime awareness calls, queries, and approaches to ensure the safety of vessels transiting these waters.

When conditions permit, maritime industry stakeholders should anticipate a deliberate and methodical plan focused on ensuring safe and secure vessel movements. This planning effort will require time to coordinate across military, interagency, and industry stakeholders.

U.S.-flagged commercial vessels should closely 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. NAVCENT NCAGS stands a 24/7 watch and has the latest information on the current maritime security threats and the operational environment in this region.

If U.S.-flagged vessels are emailed or hailed on VHF by Iranian forces operating over the horizon and instructed to divert from their planned course or submit voyage information, they should ignore the email or call and continue their passage if safe to do so. Vessels that encounter these tactics are advised not to follow Iranian directions, as doing so may enhance the ability of Iranian forces to accurately target vessels. U.S.-flagged commercial vessels are advised to update NAVCENT NCAGS when any such communications or anomalous behavior occur.

Significant GNSS interference, spoofing, and jamming continue across these areas. Given the degraded positional integrity environment, mariners should increase reliance on traditional navigation methods including radar ranges, visual bearings, and cross-checking ECDIS inputs with secondary navigation systems.

It is recommended that U.S.-flagged commercial vessels transiting these waters remain as far as possible from Iran without compromising navigational safety. When transiting eastbound in the SoH, it is recommended that vessels transit close to Oman.

U.S. citizens abroad should enroll or update their information via the Smart Traveler Enrollment Program (STEP) to get important updates and alerts from the U.S. embassy or consulate. Enrolling helps the U.S. embassy or consulate contact you or your emergency contact in an emergency. Sign up at: https://step.state.gov.

U.S.-flagged commercial vessels operating in these waters are advised to conduct a pre-voyage risk assessment, incorporate appropriate protective measures into vessel security plans, exercise caution, and monitor VHF Channel 16. In the event of any attack, incident, or suspicious activity, immediately activate the Ship Security Alert System, contact the U.S. Fifth Fleet Battle Watch, and contact the United Kingdom Maritime Trade Office (UKMTO).

U.S.-flagged commercials vessels should register with the UKMTO 24 hours prior to entering the Indian Ocean Voluntary Reporting Area shown on UK Hydrographic Office Maritime Security Chart Q6099 (https://cd.royalnavy.mod.uk/-/media/ukmto/charts/q6099.pdf) utilizing the Initial Report and subsequent reports at https://www.ukmto.org/reporting-formats. Include estimated times of arrival at the SoH, Bab al-Mandeb Strait (BAM), and/or Suez Canal in the “Destination and estimated time of arrival” field of the report and add additional comments as needed (e.g., speed restrictions or other constraints, anticipated time of entering/exiting the SoH Traffic Separation Scheme, an outline of the vessel’s navigation plan for operating in the Persian Gulf, etc.) in the same Destination field. These reports will automatically be forwarded to NAVCENT NCAGS.

Vessels operating in this area are advised to include the NAVCENT NCAGS watch on all update and incident report emails.

The Maritime Global Security website at https://www.maritimeglobalsecurity.org/ offers industry-issued best practices and guidance to mariners by geographic region and provides contact and subscription information for regional maritime security reporting centers, particularly in high risk-areas.

Due to the risks of piracy, kidnapping, hijacking, and robbery while operating within U.S. Coast Guard designated High-Risk Waters (HRW), U.S.-flagged commercial vessels are required to comply with the Guidelines for U.S. Vessels Operating in High-Risk Waters contained in U.S. Coast Guard Maritime Security Directive 104-6 (Rev 9) and comply with their Coast Guard approved Vessel Security Plan annex on counter piracy. U.S. vessel owners and operators needing access to MARSEC Directive 104–6 should immediately contact their local Coast Guard Captain of the Port or District Commander for a copy of Revision 9.

Per 33 CFR 101.305, report all suspicious activities, breaches of security, and transportation security incident events involving U.S. vessels or persons to the U.S. Coast Guard National Response Center. Additional U.S. Coast Guard port specific requirements may be found in Port Security Advisory 1-26 at https://www.dco.uscg.mil/Portals/9/DCO%20Documents/InternationalPortSecurity/Port%20Security%20Advisory/PSA%201-26-Revocation%20of%20Exemptions.pdf?ver=RuQCjWBNC51lPgfU8b77AQ%3d%3d.

4. Contact Information:

a) Fifth Fleet Battle Watch: cusnc.bwc.mil@us.navy.mil or + 1-813-529-7430.

b) NAVCENT NCAGS: +1-813-529-7108 (Primary/Watch Desk), +973-3986-4800 (Alternate), or m-ba-navcent-ncags@us.navy.mil or m-ba-navcent-ncags-ice@us.navy.mil.

c) UKMTO: watchkeepers@ukmto.org or +44 (0) 2392 222060. UKMTO advisories and warnings are available at https://www.ukmto.org/.

d) U.S. Coast Guard National Response Center: +1-800-424-8802.

5. Cancellation of Prior Advisory: This message supersedes and cancels U.S. Maritime Advisory 2026-001 and will automatically expire on September 9th, 2026.

For maritime industry questions about this Advisory, contact the Global Maritime Operational Threat Response Coordination Center at GMCC@uscg.mil. Supplemental information about U.S. Maritime Alerts and Advisories, including subscription details, may be found at: https://www.maritime.dot.gov/msci. Feedback provided by U.S. maritime industry stakeholders regarding the U.S. Maritime Advisory System has greatly supported the USG in pursuing continued enhancements to this system. Feedback to MARADSecurity@dot.gov is always welcome.