Vessel Documentation Required for Strait of Hormuz Transit

Published: 15 March 2025 · Last updated: 31 October 2026

A complete and accurate transit clearance application depends on having the right vessel documentation to hand before you begin. This guide covers every document type and data point required for a Strait of Hormuz transit clearance application, explaining where each comes from and why it is needed.

IMO vessel identification number

The IMO number is a seven-digit unique identifier permanently assigned to a vessel by IHS Markit (trading as LRFAIRPLAY) on behalf of the International Maritime Organization. Unlike a vessel's name, call sign, or flag state, the IMO number does not change when the vessel is sold, renamed, or reflagged. It is the most reliable identifier for a commercial vessel.

The IMO number is required at the first step of every transit clearance application. It is stamped on the vessel's certificate of registry, safety certificates, and classification certificate. It is also painted or engraved on the hull of SOLAS-convention ships. If you cannot locate the number, it can be searched free of charge on the IMO GISIS database.

MMSI number

The Maritime Mobile Service Identity (MMSI) is a nine-digit number used to identify a vessel in VHF digital selective calling (DSC) and in Automatic Identification System (AIS) transmissions. The MMSI is assigned by the vessel's flag state administration or by an authorised telecommunications authority. It appears in the vessel's radio station licence.

MMSI data is used by the HTCA to cross-reference AIS vessel position data with applications, enabling live corridor tracking on the vessel positions board.

Flag state and certificate of registry

The flag state is the country under whose laws the vessel is registered. The certificate of registry (also called the certificate of nationality in some jurisdictions) is the primary proof of registration. It states the vessel's name, IMO number, registered owner, gross tonnage, and port of registry.

Major flag states for vessels transiting the Strait of Hormuz include Panama, Marshall Islands, Liberia, the Bahamas, Hong Kong, Singapore, and Malta. Each flag state has its own survey and certification requirements, but all SOLAS-convention vessels must carry an up-to-date certificate of registry.

Certificate of class

Commercial vessels are surveyed by a recognised classification society — such as Lloyd's Register, Bureau Veritas, DNV, ClassNK, or ABS — which issues a class certificate confirming the vessel meets structural and engineering standards. The class certificate must be in date; a vessel operating outside class is uninsurable and may be detained by port state control.

The transit clearance application requests the vessel's classification society. While the full class certificate need not be submitted at application, HTCA reserves the right to request it before issuing a certificate where there is reason to question the vessel's fitness for transit.

Gross tonnage and deadweight tonnage

Gross tonnage (GT) is a dimensionless measure of the vessel's overall internal volume, calculated under the International Convention on Tonnage Measurement of Ships 1969. It appears on the International Tonnage Certificate and on the certificate of registry.

Deadweight tonnage (DWT) measures the total weight a vessel can carry — cargo, fuel, stores, crew, and provisions — expressed in metric tonnes. DWT is the basis for the HTCA's tiered fee structure: larger vessels carrying more cargo pay a higher clearance fee. See the full fee schedule for current DWT tier rates.

Both figures are found on the vessel's International Tonnage Certificate and should match the ship's registry entry. Declaring an incorrect DWT to obtain a lower fee tier constitutes a material inaccuracy in the application and voids the certificate.

Cargo manifest and cargo type

The application requires declaration of the cargo type from a set of standard categories: crude oil, petroleum products, LNG/LPG, dry bulk, containers, general cargo, vehicles, chemicals, ballast, or other. If carrying a commercial cargo, the approximate cargo quantity in metric tonnes should be declared.

Ballast passages — vessels transiting without commercial cargo — must still apply for clearance and declare ballast. A vessel in ballast is still subject to the same DWT-based fee as a laden vessel, as the fee reflects corridor capacity, not cargo value.

Dangerous goods declaration

Any vessel carrying cargo classified as dangerous goods under the IMDG Code (International Maritime Dangerous Goods Code) must submit a full DG declaration as part of the transit clearance application. The declaration must identify the UN number, proper shipping name, hazard class, packing group, and total quantity for each dangerous goods consignment.

Vessels carrying bulk liquid chemicals should also reference the IBC Code (International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk). Vessels carrying liquefied gases in bulk should reference the IGC Code.

Undeclared dangerous goods are grounds for immediate certificate revocation without refund and may be referred to the relevant coastal-state authority.

P&I club details

The application requires the name of the vessel's Protection & Indemnity (P&I) club. P&I insurance covers third-party liabilities including pollution, cargo damage, and crew injury claims. Major P&I clubs include the UK P&I Club, Gard, Skuld, West of England, and the Japan P&I Club.

P&I cover is increasingly scrutinised for Gulf-transiting vessels due to war risk and sanctions exposure. Operators should confirm with their P&I club before transit that cover is not excluded or suspended for the Strait of Hormuz corridor.

Owner, operator, and management details

The application requires contact details for the ship owner or operator (the entity responsible for the vessel's commercial operation), including company name, country of incorporation, a named contact, email address, and telephone number. If the vessel is under third-party ship management, the management company's details should be provided.

The difference between ship registration and transit clearance

Ship registration (flag state registration) establishes the vessel's nationality and legal identity under maritime law. Transit clearance is a separate operational requirement specific to the Strait of Hormuz corridor. Holding a valid certificate of registry does not satisfy the transit clearance requirement, just as holding a transit clearance certificate does not substitute for port state clearance at the vessel's destination port.