U.S. Central Command (CENTCOM) will enforce a naval blockade of all Iranian ports and coastal areas effective 1400 UTC on 13 April 2026.
This blockade will be enforced in the Gulf of Oman and Arabian Sea east of the Strait of Hormuz. The blockade encompasses the entirety of the Iranian coastline to include but not limited to ports and oil terminals. The blockade applies to all vessel traffic, regardless of flag. The Administration understands that formal details of these measures, including enforcement provisions and exemptions, will be promulgated and updated through official Notice to Mariners (NTM).
Neutral vessels currently in Iranian ports have been granted a grace period to depart, as will be specified in the NTM. Following this time, any vessel entering or departing the blockaded area without authorization is subject to interception, diversion, and capture. The blockade will not impede neutral transit passage through the Strait of Hormuz to or from non-Iranian destinations. Neutral vessels may still be subject to the right of visit and search to determine the presence of contraband cargo. Humanitarian shipments including food, medical supplies, and other goods essential for survival of the civilian populations will be permitted, subject to inspection.
Additional guidelines for mariners regarding how these measures will be applied in practice, including routing, verification, and authorized transit procedures are in development. Further clarification is expected to be provided through subsequent advisories as information becomes available.
Recommendations
Mariners are strongly advised to refer to the associated NTM for authoritative detail, including geographic limits, conditions of transit, and inspection and authorization requirements. Vessels operating in the Strait of Hormuz approaches, Gulf of Oman, and adjacent waters are advised to maintain heightened awareness, ensure maximum bridge readiness, and exercise appropriate caution with bridge-to-bridge VHF communications.
All owners, operators, and crews should remain cognizant of the elevated threat in the affected area and perform detailed, vessel-specific, voyage- specific and activity specific risk assessments for any operations or transit through the affected area. Additional guidance to the threats, mitigations and considerations to transiting this area are available in the Joint Maritime Information Centre (JMIC) advisories: https://www.ukmto.org/partner-products/jmic-products
All vessels should report to the UKMTO and register with the Maritime Security Centre for the Indian Ocean (MSCIO) in accordance with industry BMP (Best Management Practices) and take advice from the coalition forces operating in the area. Best Management Practices for Maritime Security (BMPMS) will continue to provide the necessary guidance for shipping to ensure threat and risk assessments are developed for every voyage to mitigate the risks presented by remaining security threats in the region. The shipping industry will continue to monitor and advise on maritime security threats to assist the safe transit of vessels and the seafarers.
UKMTO acts as the primary point of contact for merchant vessels and liaison with military forces in the region. Vessels are encouraged to register with UKMTO and report their positions (By email daily at 08.00 UTC) whilst operating in the area.
The MSCIO is the planning and coordination centre for the EU Naval Forces (EU NAVFOR). MSCIO encourages companies to register their ships’ movements before entering the Voluntary Reporting Area (VRA).
All vessels transiting the Arabian Gulf, Strait of Hormuz, Gulf of Oman and North Araiian Sea are also encouraged to report to the Information Fusion Centre – Indian Ocean Region (IFCIOR), this is a voluntary reporting measure that promotes cooperation, stability and communication with partner stakeholders in the region as well as aligns with the most recent measures published in BMP MS. Vessels with voyages through this area can use the Vessel’s Reporting Form at IFCIOR’s website.
Contact Information
In an emergency, vessels transiting the Arabian Sea, Straits of Hormuz and Gulf of Oman should contact NAVCENT Battle Watch Phone: +1-813-529-7430, Email: cusnc.bwc.mil@us.navy.mil; Naval Cooperation and Guidance for Shipping (NCAGS) Primary Watch Floor Phone: +1-813-5297108, Alternate Mobile Phone: +973- 3986-4800, Email: m-ba-navcent-ncags@us.navy.mil or mba-navcent-ncags-ice@us.navy.mil
Contact MSCIO prior to transiting the Western Indian Ocean, the Somali Basin, Gulf of Aden, Gulf of Oman and the Red Sea. The contact details of MSCIO are: Maritime Security Centre – Indian Ocean (MSCIO) Email postmaster@mscio.eu Telephone +33 (0) 298 220 220 +33 (0) 298 220 170 Fax +44 1923 958520 Website www.ukmto.org
When transiting the Western Indian Ocean, the Somali Basin, Gulf of Aden, Gulf of Oman and Red Sea. Register their vessels with UKMTO Email: watchkeepers@ukmto.org and ukmto@eim.ae Phone: +44 – 2392-222060, +971-50-552-3215 Fax +44 1923 958520
Please keep LISCR’s Security Department informed of any security incidents at: Office of the Senior Deputy Commissioner of Maritime Affairs Republic of Liberia 22980 Indian Creek Drive, Suite 200 Dulles, Virginia 20166 USA D: +1 571 495 5944 / O: +1 703 790 3434 / F: +1 703 790 5655 Email: Security@liscr.com www.liscr.com