About maritime mobile service identity information

Why you need a maritime mobile service identity (MMSI), and how to apply for one.

We allocate maritime mobile service identity numbers (MMSI’s) to people who own a vessel or unit that has either:

  • digital selective calling (DSC) capable equipment
  • automatic identification system (AIS) units.

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What is an MMSI?

An MMSI is a unique nine digit number that is entered into certain marine radio communications equipment. When using this equipment to send a distress alert, or to indicate some other emergency, the number assists emergency services to identify you and/or your vessel.

Since marine VHF transceivers now operate under a class licence, there is no requirement for an official call sign and maritime ship station licence, but the operator must have a minimum radio operator qualification of a AWQ or Short range certificate of proficiency (Marine radio operator’s VHF certificate of proficiency). However, for MF/HF transceivers, Long range certificate (Marine radio operators certificate of proficiency) is the minimum qualification, as well as a ship station licence (including callsign) issued by the Australian Communications and Media Authority.

Why you need an MMSI

You are required to apply for an MMSI if you have the following equipment:

  • fixed very high frequency (VHF) radio with digital selective calling (DSC)
  • a handheld VHF DSC
  • high frequency (HF) DSC
  • automatic identification system (AIS)

Similar to a text message, DSC can be used to establish initial contact between vessels and stations. You are identified by your MMSI number and able to indicate the priority of your message, for instance whether it is a distress, emergency, security or routine message.

If your equipment is connected to a GPS receiver, the message will also provide the vessel’s position and time at which the position was valid. 

DSC equipment is a part of the global maritime distress and safety system (GMDSS).

AIS is an automatic system used on ships and by vessel traffic services for identifying and locating vessels (class A or class B transceiver) and for safety of navigation.

All large commercial vessels subject to the Safety of Life at Sea Convention (SOLAS) must carry DSC and AIS equipment appropriate to their area of operations. However, small recreational and fishing vessels may not require DSC equipment unless they plan to operate offshore or proceed overseas.

Coast stations may also be equipped with DSC, and in this case, also require an MMSI.

Some ports in Australia mandate the carriage by certain types of non-SOLAS vessels working in the port. State marine regulators also mandate AIS in certain types of vessels.

MMSIs are also required for shipborne or non-shipborne automatic identification system transceivers as defined in ITU-R recommendation M.1371.

How to apply for an MMSI

Apply for an Australian MMSI number by completing an MMSI application online or by downloading the form.

Before applying for an Australian MMSI number you must have:

  • An ACMA maritime ship station licence and callsign for an MF/HF transceiver
  • Vessel registered in Australia (except Northern Territory)
  • Marine radio operator qualifications1. The following types are accepted:
    • Australian waters qualification (AWQ)2, 3
    • Short range certificate of proficiency (Marine radio operators VHF certificate of proficiency)3
    • Long range certificate (Marine radio operators certificate of proficiency)
    • GMDSS first class radio electronic certificate – 1st class REC
    • GMDSS second class radio electronic certificate – 2nd class REC
    • GMDSS general operator's certificate – GOC
    • Restricted radio operator's certificate of proficiency

You will also need to provide the following information:

  • name, address and phone numbers of registered vessel owner
  • name and phone numbers of at least one person who can act as a 24-hour emergency contact
  • vessel, vehicle or aircraft details as applicable
  • VHF DSC, HF DSC or AIS make or model, or Handheld VHF DSC make or model and serial number.

1 Marine radio operator qualifications are not required for AIS on SAR aircraft, AIS base stations or AIS aids to navigation.
2 AWQ is accepted for VHF and AIS operating in Australian waters only.
3 Diver handheld VHF DSC transceivers – marine radio operator qualifications are not required if the radio operator in the diving boat (mother vessel) is qualified. In the case of lone divers not operating from boats, the requirement for a marine radio operator certificate remains.

MMSI online application forms

To apply for an MMSI, you can use the online form, or choose one of the options below.

Option 1

For Australian registered vessels, coast stations, handheld VHF radios with DSC and AIS on SAR aircraft, apply for an Australian MMSI number by completing MMSI application form 89.

Option 2

For Australian AIS base stations and AIS aids to navigation, apply for an MMSI by completing one of the following forms:

MMSI enquiries

Phone: 1800 406 406 or +61 02 6279 5000 (international callers)

Email: ausbeacon@amsa.gov.au

Access an MMSI application form:

DSC identification

To use DSC techniques, an MF/HF DSC, VHF DSC and/or AIS transceiver must be permanently programmed with an MMSI. This can be regarded as the electronic equivalent of a radio call sign and uniquely identifies that ship or coast station. It is important to recognize that the MMSI identifies the vessel or coast station, and if more than one fixed transceiver and/or AIS transceiver is carried they are all to be programmed with the same MMSI. A vessel's 406 MHz emergency position indicating radio beacon (EPIRB) may also be programmed with the same MMSI. The selling agent can program the MMSI into the transceiver and AIS equipment.

The MMSI is automatically included in all DSC and AIS transmissions from a station and electronically identifies that station to the receiving station(s).

MMSI formats

Three of the nine digits of an MMSI identify country of origin. In the case of a coast station these digits indicate the country of location, and in the case of a ship station, the country of registration. The remaining six digits uniquely identify the station itself. The three digits identifying the country are known as the maritime identification digits or MID. Australia's MID is 503.

An Australian vessel MMSI takes the form 503xxxxxxwhere x is any figure from 0 to 9.

An Australian coast station MMSI takes the form 00503xxxx where the first two figures are zero and x is any figure 0 to 9.

A full international list of MIDs appears in list VIIA, list of callsigns and numerical identities published by the International Telecommunication Union (ITU), the ITU Manual for use by the Maritime Mobile and Maritime Mobile-Satellite Services and the Australian Global Maritime Distress and Safety System (GMDSS) Handbook.

Group MMSIs

Groups of vessels can be called via DSC by a group ID or group MMSI. Group MMSIs are finding use by fleets and yacht races. Safety and urgency DSC calls (Announcements) can be sent to a group MMSI. Each vessel desiring to be part of a group would enter the same group MMSI into their DSC equipment, which usually can be named for convenience by the user.

Group MMSI numbers begin with a single 0 before the MID, so it takes the form 0503xxxxx (where x is any figure from 0 to 9).

Group MMSIs can be manually programmed into a DSC-equipped transceiver by the user at will (unlike the self-ID). Any number with a leading zero can be used as a group MMSI, and they do not need to be registered, but the entity deciding on a group MMSI must use the MID of the host country or country of vessel registration.

The group ID should be based on a key vessel in the group, and a good way to proceed is to drop the last digit of the lead vessel’s MMSI and place a zero in front of the 503 as follows:

Example 1: a fleet of vessels has a lead or main vessel with a DSC self-ID of 503123456 and wishes to set up a group MMSI for a special event. The group ID could be 050312345.

This would then be programmed into all fleet vessels as the special event group MMSI.

Example 2: a fleet of vessels has a lead or main vessel with a DSC self-ID of 503080110. The group MMSI could be 050308011. This would then be programmed into all fleet vessels as the special event group MMSI.

Group MMSI numbers are not to be used for AIS transceivers.

Maritime identities for handheld portable VHF DSC transceivers

We recognise the safety potential of VHF marine transceivers with DSC capability. Our policy for these units are to allocate MMSIs to individual radio transceivers rather than to a single vessel-specific MMSI. In Australia, until January 2012, these transceivers' maritime identities had the format 5039xxxxx where x is any figure from 0 to 9.

From January 2012, Australian handheld VHF transceivers with DSC now use the maritime identity format 8503xxxxx, where x is any figure from 0 to 9, in accordance with recommendation ITU-R M.585-6, annex II, section I.

When a handheld VHF transceiver with DSC changes ownership, we need to be advised of the new owner's details.

Handheld VHF transceivers with DSC are issued to persons, rather than vessels, in recognition that these transceivers can move between vessels.

The requirement to present a copy of an appropriate radio operator's qualification when applying for an MMSI also applies to MMSIs requested for the portable VHF DSC transceivers.

Diver handheld VHF DSC transceivers

Effective as from November 2013, the Australian Communications and Media Authority does not mandate a marine radio operator certificate prior to the issuing of an MMSI for personally attached diver VHF radios, that offer a digital selective calling transmit capability, and limited voice communications. This presumes that the radio operator in the diving boat (mother vessel) is qualified. In the case of lone divers not operating from boats, the requirement for a marine radio operator certificate remains.

MOB / MSLS devices using VHF DSC channel 70

Maritime survivor locating systems or man overboard devices compliant with AS/NZS 4869.4 may use distress alerts via DSC using VHF DSC channel 70. In Australia, you can use automated voice announcements indicating distress using the man overboard indication on the distress, urgency and safety and calling frequency of 156.8 MHz (VHF channel 16).

Such low-power devices also may indicate the position of the man overboard distress in the DSC message and/or in Australia, the voice message. Such announcements have distress priority and are to be treated as distress transmissions. Stations receiving these alerts should be aware that these alerts and messages are one-way broadcast messages to all stations in range, and cannot be acknowledged of cancelled until the battery is exhausted or sinks.

Some of these devices, developed for overseas markets, contain a DSC receiver, which allows acknowledgment or cancellation by a coast station or SOLAS vessel (but only under direction of a coast station or the JRCC as per IMO COMSAR/Circ.25).

The intention of these devices is to enable vessels and coast stations in range to facilitate rescue of persons in distress in the shortest possible time.

MOB/MSLS devices using automatic Iientification system frequencies

A number of devices used as man overboard devices (maritime survivor locating systems or devices) use AIS technology based on the on burst transmissions defined in annex 9 of recommendation ITU-R M.1371. Early versions of these devices have the maritime identity of the format 970xxyyyy, but newer units starting from 2011, use the format 972xxyyyy1, which has been internationally agreed in recommendation ITU-R M.585-6, annex 2, section 2.

There is currently no AS/NZS standard for these devices, but they should be certified by a competent testing house that they are sufficiently compliant with the IEC 61097-14 for the purpose it is intended, or fully compliant with overseas standards, such as RTCM 11901.1 (June 2012). Additional overseas standards for these devices are under development.

1 Maritime survivor locating systems (AS/NZS 4869.4) until January 2012 used the maritime identity in the format 5038XXXXX. These systems now use the internationally agreed format 972xxyyyy, where x and y are any numbers between 0 and 9. The number is pre-programmed. The xx numbers are allocated to manufacturers by the International Association for Marine Electronics Companies (CIRM), and the yyyy numbers are allocated by the manufacturer as sequential numbers. In accordance with recommendation ITU-R M.585-6, the sequential numbers can be re-used once 9999 is reached. AMSA does not allocate these numbers, and no radio operator licence is required.

Diver locating systems using AIS

Some diver locating devices use technology based on burst transmissions defined in annex 9 of recommendation ITU-R M.1371, in a similar way to man overboard devices. The International Maritime Organization (NAV 58) has agreed that diver locating devices used for routine diver operations should not operate on the international AIS frequencies 161.975 MHz (AIS 1) or 162.025 MHz (AIS 2). AIS 1 and AIS 2 should only be used when a diver is in a non-routine situation. The associated text transmitted in a non-routine diver situation should be MOB ACTIVE (or MOB TEST in test mode). The maritime identifier in this situation should be the same as for MOB devices: eg. 972xxyyyy, as described above.

Summary of Australian MMSI formats in current usage

In this table, x or y to be any figure 0 through 9.

Type of stationMMSI format
Automatic identification systems (AIS)
DSC equipment
Ship stations503xxxxxx
Craft associated with a parent ship98503xxxx
SAR aircraft111503xxx
Handheld portable VHF DSC (Australia only)5039xxxxx (until Jan. 2012)
Handheld portable VHF DSC8503xxxxx (after Jan. 2012)
Group of ship stations0503xxxxx
Coast station00503xxxx
Man overboard (MOB/MSLS) devices15038XXXXX (until Jan. 2012 - Australia only)
Man overboard (MOB/MSLS) devices1972xxyyyy
AIS class A/B transceivers503xxxxxx or 503xxx000
AIS base stations (incl. repeaters)00503xxxx
Physical (real) AIS aids to navigation (AtoN)2995031xxx
Synthetic AIS aids to navigation (AtoN)3995031xxx
Virtual AIS aids to navigation (AtoN)4995036xxx
AIS on craft associated with parent ship498503xxxx
AIS-SARTs (AIS-search and rescue transmitters)6970xxyyyy
Man overboard (MOB/MSLS) devices1972xxyyyy
406 MHz EPIRBs fitted with an AIS transmitter974xxyyyy
AIS on SAR aircraft7111503xxx

1Maritime survivor locating systems (AS/NZS 4869.4) until January 2012 used the maritime identity in the format 5038XXXXX, but now use the internationally agreed format 972xxyyyy, where x and y are any numbers between 0 and 9. The number is pre-programmed. The xx numbers are allocated to manufacturers by the International Association for Marine Electronics Companies (CIRM), and the yyyy numbers are allocated by the manufacturer as sequential numbers. In accordance with recommendation ITU-R M.585-6, the sequential numbers can be re-used once 9999 is reached. AMSA does not allocate these numbers, and no radio operator licence is required.

2AIS fitted to physical aids to navigation such as floating buoys and beacons.

3AIS base stations can broadcast a non-physical synthetic AIS AtoN to appear at the location of a real physical AtoN on an AIS-enabled display system— for example AIS, ECDIS or radar.

4AIS base stations can broadcast a non-physical virtual AIS AtoN at a particular location when no physical AtoN exists.

5AIS on workboats or other vessels deployed from a parent vessel.

6AIS-SARTs are survival craft SAR-locating devices which can be carried in-lieu of radar SARTs on SOLAS vessels from 1 January 2010, and can be carried on non-SOLAS vessels for similar purposes.

7EPIRBs fitted with an AIS transmitter use the maritime identity format 974xxyyyy for the AIS transmission, so as to be distinguished from other devices using AIS, where x and y are any numbers between 0 and 9. The number is pre-programmed. The xx numbers are allocated to manufacturers by the International Association for Marine Electronics Companies (CIRM), and the yyyy numbers are allocated by the manufacturer as sequential numbers. In accordance with recommendation ITU-R M.585-6, the sequential numbers can be re-used once 9999 is reached. This number is allocated by the manufacturer, and not AMSA, and should not be confused with the HEX ID or Unique Identifier used in EPIRBs, ELTs and PLBs. AMSA does not allocate these numbers, and no radio operator licence is required.

8AIS on SAR aircraft is a variant of AIS specifically for SAR. AIS can also be used for safety-related purposes on non-SAR aircraft (such as marine pilot-transfer helicopters).

Operator qualifications and licence requirements

To operate a VHF transceiver with or without DSC fitted, the minimum radio operator qualification required is the AWQ or Short range certificate of proficiency (Marine radio operator’s VHF certificate of proficiency). The same requirement exists for AIS transceivers. VHF transceivers and AIS transceivers are covered by an ACMA class licence, so an individual station licence is no longer required.

To operate an MF/HF transceiver (with or without DSC facilities) a Long range certificate (Marine radio operators certificate of proficiency) is the minimum qualification required. A separate maritime ship station licence is also required, which is issued by the Australian Communications and Media Authority.

Aviation radio operator qualifications are not accepted for AIS or DSC equipment carried aboard vessels. Aviation radio operator qualifications are only acceptable for AIS or DSC fitted to an aircraft.

The Marine Radio Operators Handbook provides further information about qualifications, licensing and DSC operations.

Maritime communication station facilities for DSC

Australia has declared the whole of the Australian SAR region as GMDSS sea area A3 which gives large commercial ships the option of using Inmarsat or HF DSC as a primary means of communications and distress alerting.

Two HF DSC stations operated by Kordia provide HF DSC distress alerting and follow-on communications on radio telephony and narrow band direct printing (NBDP). The stations are located at Wiluna in WA, and Charleville in Qld, and are operated remotely from Canberra.

Any vessel fitted with appropriate HF DSC equipment can call into the HF DSC network.

The states and Northern Territory are responsible for marine safety communication services for recreational, fishing and other commercial vessels within their jurisdiction.

The states and Northern Territory have implemented a network of 9 HF limited coast stations which monitor 4125, 6215, and 8291 kHz and broadcast navigation warnings on 8176 kHz and VHF Ch.67. These stations also monitor VHF channel 16 and may also monitor other marine frequencies.

There is no official MF or VHF DSC shore infrastructure in Australia. Vessels fitting MF and VHF DSC equipment should realise that this equipment can only be used for vessel to vessel alerting in the Australian region. There is no official shore-based MF or VHF DSC infrastructure, but there are a number of volunteer marine rescue (VMR) stations that have installed VHF DSC and a check with your local VMR should be made.

Small craft proceeding overseas

It is recommended that smaller craft planning voyages overseas check the radio facilities offered along their route. Whilst large commercial vessels subject to the SOLAS Convention are required to keep a watch on channel 16 VHF when practicable, there may be a case to fit VHF DSC along with some form of long range communications such as Inmarsat-C. Compatibility with GMDSS services is strongly recommended. Details of GMDSS radio facilities offered around the world can be found in the Admiralty List of Radio Signals Volume V, published by the UK Hydrographic Office and available through most chart and publication shops.

Search for MMSI

Search for an Australian MMSI number.

Further information
Last updated: 15 July 2020