What is the MMSI or Maritime Mobile Service Identification number?

Surely if you are dedicated to sailing you have heard on many occasions about the MMSI. What is this identification number and when is it appropriate to have it? This is an element of great relevance for the purposes of radio communications and the safety of a ship and, in Spain, they depend directly on the General Directorate of the Merchant Navy. Let's see what exactly it consists of.

What is MMSI exactly?

When we talk about the MMSI we refer to the Maritime Mobile Service Identification Number, as its acronym in English indicates –Marine Mobile Service Identity-. A piece of information made up of nine digits with which individually identifies all stations of the digital mobile service, both ship and coastal stations.

In turn, this classification mode is included in the Global Maritime Distress and Safety System, known as GMDSS. MMSI identification is mandatory and it can be required by the authorities at any time, so it is advisable to request it and understand what it is for and what each of the digits that make it up mean. Some boats have this identification on their registration.

How is the MMSI number made up and what does each digit indicate?

Taking into account that the MMSI identifies both coast stations and ship stations, it is worth noting a difference in the issuance of numbers. And, while the first ones always begin with 00, followed by the three figures that make up the MID –Maritime Identification Digits-, the MMSI of a ship begins directly with these first three digits.

From there, in both cases we find the rest of the digits that refer to the particular identification of each station integrated in the Digital Mobile Service. As all MMSIs have 9 digits, those corresponding to vessels have 6 more individual characters and land stations have 4, since the number always begins with 00.

What is the MMSI for?

Really, What is the MMSI for? We already know that we are dealing with an identification number, but it is essential to know what its application is in nautical. Well, this identification must be programmed in the ships' radio communications equipment and radio beacons, so that it is transmitted digitally by radio frequency and through LSD -Digital Selective Call-.

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MMSI Identification Types

At this time there are different typologies regarding MMSI identification depending on the type of stations they identify and whether it is an individual or group call identity. That is, we find MMSI for coast stations and for groups of coast stations, in addition to MMSIs for individual ship stations and for making calls to groups of ships. 

Specifications regarding the MMSI, what do you need to know?

Beyond knowing what the MMSI is and what it is for, it is interesting to clarify issues such as the procedure with the identification number in emergency situations, how to request the Maritime Mobile Service Identification Number and in what regulations its obligation is reflected.

The legal framework of the MMSI

The current reference regulation in which the regulatory specifications of the MMSI are established is the Article 19 of the ITU Communications Regulations, as well as in Article 5 of the Royal Decree 1185/2006.

The MMSI issuance depends on the Radiocommunications Area of the Directorate of the Merchant Navy for vessels larger than 24 meters in length and for land stations, while in the case of vessels smaller than this size, it must be requested in the Sea captaincy corresponding to each zone.

How to proceed in emergency situations

When an emergency occurs that requires action through the radio communications and security equipment of a vessel, it is essential that there be a operating procedures chart in relief situations. This protocol must always remain available - and in Spanish in the case of vessels from this country - and in a visible place, in addition to including all the vessel's data - including the MMSI.

How do you request the MMSI?

To request the MMSI it is necessary to present the application form MMSI assignment request -and the assignment of MMSI for AtoN-, pay the fees established at any time and contribute the proof of payment and the authorization of the shipowner in case he is not the one requesting the document directly. This request can be made at the Maritime Captaincy.

The MMSI and radio communication, essential elements in a ship

For navigation lovers, safety is a fundamental aspect, and radio communications are one of the main elements in this sense. Beyond its obligation, Applying for the MMSI guarantees being part of the Global Maritime Distress and Safety System, which facilitates rescue and navigation in certain dangerous situations.