====== International distress frequency ======
===== Current frequencies =====
International distress frequencies, currently in use are:
  * 2182 kHz for medium range maritime voice use. The US Coast Guard has said "beginning August 1st, 2013 the Coast Guard would no longer monitor 2182 kHz",[4] as have many other coast guard services.
  * Several HF maritime voice frequencies exist for long-distance distress calls:[5]
      * 4.125 MHz
      * 6.215 MHz
      * 8.291 MHz
      * 12.290 MHz
      * 16.420 MHz
  * 121.5 MHz is the civilian aircraft emergency frequency or International Air Distress frequency. It is used by civilian distress radiobeacons; however, the Cospas-Sarsat system no longer monitors the frequency.
  * 243 MHz for NATO military aircraft emergency frequencies
  * Marine VHF radio Channel 16 (156.8 MHz) for short range maritime use
  * 406 MHz to 406.1 MHz is used by the Cospas-Sarsat international satellite-based search and rescue (SAR) distress alert detection and information distribution system
  * 462.675 MHz is a UHF mobile distress and road information calling frequency allocated to the General Mobile Radio Service and used throughout Alaska and Canada for emergency communications; formerly called Orange Dot in the 1960s, "GMRS 675" or Channel 6 on mobile radios today. Its bandwidth can vary between 12.5, 25 and 50 kHz, and is also allocated to Ch. 20 on 22-channel FRS/GMRS "blister pack" radios. It can have a repeater input frequency of 467.675 MHz, and a tone squelch of 141.3 Hz.

===== Digital selective calling frequencies =====
Several maritime frequencies are used for digital selective calling (DSC), and they are also monitored for DSC distress signals:
  * 2.1875 MHz
  * 4.2075 MHz
  * 6.312 MHz
  * 8.4145 MHz
  * 12.577 MHz
  * 16.8045 MHz
  * 156.525 MHz, Marine VHF radio Channel 70

===== Amateur radio frequencies =====
  * Emergency Centre of Activity (ECOA) frequencies informally established by the International Amateur Radio Union regional organizations (frequencies shown in kHz):

^ Region 1 \\ Europe, Africa ^ Region 2 \\ The Americas ^ Region 3 \\ Asia ^
| 3760 | 3750 or 3985 | 3600 |
| 7110 | 7060, 7240 or 7275 | 7110 |
| 14300 | 14300 | 14300 |
| 18160 | 18160 | 18160 |
| 21360 | 21360 | 21360 |

  * Emergency/Disaster Relief Interoperation Voice Channels of the amateur radio Global ALE High Frequency Network:
      * 3791.0 kHz USB
      * 7185.5 kHz USB
      * 10145.5 kHz USB
      * 14346.0 kHz USB
      * 18117.5 kHz USB
      * 21432.5 kHz USB
      * 24932.0 kHz USB
      * 28312.5 kHz USB
  * Citizens band (CB) radio (not available in all countries)
      * Emergency channels 9 (27.065 MHz AM) and 19 (27.185 MHz AM)