Search and Rescue in Australia
Distress and Safety Communications
- GMDSS concept
- GMDSS services provided by AMSA
- AMSA HF DSC network
- Maritime radio services for small craft
- Maritime Safety Information
- Maritime Mobile Service Identity
- AUSREP and REEFREP

Maritime Mobile Service Identity (MMSI)
Introduction
Australian Search and Rescue (AusSAR), a part of AMSA, allocates and issues MMSI to Australian vessels. The Registration database is held at RCC Australia. The following information is provided as background and to assist in determining whether a vessel should request an MMSI. All large commercial vessels subject to the Safety of Life at Sea (SOLAS) Convention must carry DSC 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.
Is a call sign or Maritime Mobile Service Identity (MMSI) needed?
An MMSI is a unique nine-digit code set into your DSC terminal to identify your vessel. You need only one of these if you have multiple DSC radios. You use the same MMSI for all radios onboard the one vessel as it is a Ship's identity. Because VHF radios now operate under a Class Licence, there is no requirement for an official call sign but an Operator must have a Maritime Radio Operators Certificate of Proficiency (MROCP).
To download the brochure Digital Selective Calling - Frequently Asked Questions, click here.
DSC Identification
To use DSC techniques, an MF/HF or VHF DSC transceiver must be permanently programmed with a unique nine-digit identification number known as the Maritime Mobile Service Identity (MMSI). This can be regarded as the electronic equivalent of a radio call sign and uniquely identifies that coast or ship station. It is important to recognize that the MMSI identifies the vessel and if more than one radio is carried they are 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 radio equipment.
The MMSI is automatically included in all DSC transmissions from a station and electronically identifies that station to the receiving station(s).
To download the brochure Digital Selective Calling - Frequently Asked Questions, click here.
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 MMSI takes the form 503xxxxxx where x is any number from 0 to 9.
An Australian coast station MMSI takes the form 00503xxxxxx where the first two figures are zero and x is any figure 0 to 9.
Group MMSI numbers begin with a single 0 before the MID, so it takes the form 0503xxxxxx (where x is any number from 0 to 9). Group MMSIs can be manually programmed into a DSC-equipped radio 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 should use the MID of the host country. Group MMSIs are finding use by fleets and yacht races. Safety and Urgency 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.
MMSIs for Handheld "portable" VHF DSC-equipment transceivers.
AMSA recognises the safety potential of VHF marine transceivers with DSC capability. AMSA's policy for these units is to allocate MMSIs to individual radio transceivers rather single vessel-specific MMSI. In Australia, these transceivers' MMSIs will have the format 5039XXXXX.
These "portable" VHF DSC transceivers are only currently approved for DSC use on Australian vessels in Australian waters. When a handheld VHF transceiver changes ownership, AMSA is to be advised of the new owner's details.
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 described above.
A full international list of MIDs appears in Appendix 43 of the Radio Regulations published by the International Telecommunications Union (ITU).
Operator qualifications and licence requirements
To operate a VHF radio with or without DSC fitted the minimum qualification required is the Marine Radio Operators VHF Certificate of Proficiency (MROVCP). VHF radios are covered by a class license. An individual station license is no longer required.
To operate an MF/HF radio (with or without DSC facilities) a Marine Radio Operators Certificate of Proficiency (MROCP) is the minimum qualification required. A Ship Station license is also required.
The Marine Radio Operators Handbook provides further information about qualifications, licensing and DSC operations.
Can you use a DSC Radio correctly?
Maritime Communication Station facilities for DSC
Australia has declared the whole of the Australia Search and Rescue 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 THL provide HF DSC distress alerting and follow-on communications on radiotelephony 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 State/Territories are responsible for marine safety communication services for recreational craft and fishing vessels.
The States/Territories have implemented a network of HF voice stations which monitor 4125, 6215, and 8291 kHz. VHF channel 16 and 67 services are also provided in various locations.
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 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.
To download the brochure Digital Selective Calling - Frequently Asked Questions, click here.
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 British Admiralty and available through most chart and publication shops.
MMSI application
A form is available for boat owners to fill in to apply for an Australian MMSI. To be eligible for issue of an Australian Maritime Mobile Service Identity (MMSI) number you must have previously obtained an ACA licence number and callsign for an HF radio and a Marine Radio Operator's Certificate of Proficiency (MROCP), or a GMDSS General Operator's Certificate of Proficiency (GOCP). For a VHF only installation the radio will be covered by a class license but the minimum qualification required is a MROVCP.
Fill online and print application form
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PDF: 80KB]
If you are unable to download the above form, a hard copy can be faxed or posted to you. Please contact the database manager by emailor by phone on 1800 406 406.
Search for MMSI
last updated:
1 December 2005







