How to Send an SOS in Morse Code: The Universal Emergency Signal

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Morse Code

Morse Code

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Key Takeaways

  • The SOS Pattern: Three short dots, three long dashes, and three short dots (... --- ...).
  • No Pauses: Unlike normal Morse code words, SOS is sent as one continuous signal without breaks between the letters.
  • Visual Signals: You can use a flashlight or mirror to flash the SOS pattern.
  • Audio Signals: A whistle, car horn, or simply banging on a pipe can be used to tap out SOS.

If you ever find yourself lost, trapped, or in a critical emergency, knowing how to ask for help is vital. The most universally recognized distress signal in the world is SOS.

Originally established in 1905 for maritime emergencies, the SOS signal was chosen not because it stands for "Save Our Ship" (a common myth), but because its Morse code pattern is incredibly distinctive and easy to transmit.

Here is exactly how to send an SOS in Morse code using sound or light.

What is the SOS Morse Code Pattern?

In Morse code, the letter S is three short dots (. . .) and the letter O is three long dashes (- - -).

Therefore, the SOS pattern is: Dot Dot Dot – Dash Dash Dash – Dot Dot Dot

Importantly, when sending an SOS, you do not pause between the letters like you would in a normal sentence. It is sent as one continuous sequence: ...---.... This unbroken rhythm makes it instantly recognizable, even to people who do not know the rest of the Morse code alphabet.

How to Flash an SOS with Light

If you are stranded at night or trying to signal a passing ship or aircraft, visual signals are your best option. You can use a flashlight, the strobe function on your phone, or a signaling mirror during the day.

  1. Three short flashes: Turn your light on and off rapidly three times. (Each flash should last about one second).
  2. Three long flashes: Turn your light on and off three times, leaving it on for three seconds each time.
  3. Three short flashes: Repeat the rapid on-and-off sequence three times.
  4. Pause: Wait for about five seconds, and then repeat the entire sequence.

If you want to see exactly what this looks like, you can test our Morse Code to Light tool to watch a simulation of the SOS flash.

How to Tap or Sound an SOS

If you cannot be seen, you must be heard. You can send an audio SOS using a whistle, a car horn, or by striking two rocks together.

  1. Three short blasts: Blow three quick, sharp bursts on a whistle (or tap three times quickly).
  2. Three long blasts: Blow three long, sustained blasts. (Hold each blast for about three times the length of the short ones).
  3. Three short blasts: Blow three quick bursts again.
  4. Pause: Wait a moment and repeat.

Rescuers are trained to listen for rhythmic, unnatural patterns in the wild. The repetitive nature of the SOS signal cuts through the noise of wind or traffic. You can practice recognizing the audio rhythm using our Morse Code to Audio tool.

Practice Makes Perfect

In a high-stress emergency, you won't have time to look up instructions. Memorize the rhythm of three shorts, three longs, and three shorts.

You can try practicing right now by typing SOS into our primary Morse Code Generator to hear and see the universal distress signal in action.