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Marine radio protocols and procedures

National and international systems exist to provide search and rescue assistance to ships in distress. Using the correct radio protocols and procedures ensures these systems work effectively.

Calling and working

Always listen before calling, to make sure you are not causing harmful interference to existing communications.

When calling and working with another maritime station, establish communications on a calling frequency. For VHF, this is channel 16.

Once communications have been established, switch to a working channel or frequency. For VHF, use channels 72, 73 or 77 when working with other vessels. When calling and working with a coast station use channel 73.

Calling and working frequencies for HF marine radio are in the maritime ship station LCD.

Distress, urgency and safety transmissions

A distress call has priority over all other transmissions.

On VHF, use channel 16 or 67 for distress transmissions. In the MF/HF marine bands, use 2182 kHz, 4125 kHz, 6215 kHz, 8291 kHz, 12 290 kHz or 16 420 kHz.


  • choose the lowest licensed frequency and move to higher ones until you find one that works, if you are using the MF/HF marine bands
  • listen before transmitting to ensure the channel is not already in use

Marine radio qualifications

All operators of marine radios (except 27MHz) are required to hold the appropriate qualification to operate the device.

Marine radio operators handbooks

The Australian Maritime College has handbooks explaining how to operate a radio. Copies of the handbooks are available online.

 You can also buy a copy of the handbooks from the college.

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