What is the Morse Code for SOS?
SOS in Morse code is · · · − − − · · · — three dots, three dashes, three dots. It is the internationally recognised distress signal, used to call for help in life-threatening emergencies.
SOS was chosen specifically because it is simple and unmistakable. The pattern is symmetrical, easy to send even under stress, and impossible to confuse with any other signal. There is no word break between the three letters — it is sent as one continuous sequence of 9 signals.
Contrary to popular belief, SOS does not officially stand for anything. "Save Our Souls" and "Save Our Ship" are backronyms coined after the signal was adopted. The letters were simply chosen for their simplicity in Morse code.
How to Send an SOS Signal
No radio? You can signal SOS with almost anything that produces light, sound or movement.
Radio / Morse key
The classic method — short-short-short, long-long-long, short-short-short on any radio transmitter or Morse key. On international distress frequencies (500 kHz, 156.8 MHz).
Torch or phone light
Flash your torch — 3 short flashes, 3 long flashes, 3 short flashes — repeatedly with a pause between each full sequence. Visible at night up to several miles.
Mirror (heliograph)
Reflect sunlight using a mirror, phone screen or any shiny surface. Aim at aircraft or ships. The reflected flash can be seen up to 10 miles away in daylight.
Horn, whistle or tapping
3 short blasts, 3 long blasts, 3 short blasts on a whistle, horn or by tapping on a pipe. Short = 1 second, long = 3 seconds. Repeat every minute.
Fire and smoke signals
Three fires in a triangle is a universal distress signal recognised by search and rescue. During the day, produce smoke by adding green leaves, rubber or plastic — smoke is more visible than flame. At night, bright flame is more effective.
The History of SOS
Before SOS, ships used the distress signal CQD — a general call (CQ) followed by D for distress. But CQD was complex, easy to confuse, and not universally recognised.
In 1906, the International Radiotelegraph Convention in Berlin considered alternatives. The signal · · · − − − · · · was proposed because of its simplicity and symmetry — impossible to misinterpret even in poor signal conditions.
SOS was formally adopted internationally in 1908. The Titanic in 1912 was among the first ships to use both CQD and SOS during its distress transmissions — the operator sent both to ensure any nearby ship would recognise it.
Today SOS remains the standard visual and acoustic distress signal worldwide, even though digital distress systems like EPIRB have largely replaced Morse code radio transmission in maritime use.
Frequently Asked Questions
What does SOS stand for in Morse code?
SOS does not officially stand for anything. It was chosen because the pattern · · · − − − · · · is simple, symmetrical and impossible to misread. "Save Our Souls" and "Save Our Ship" are popular backronyms invented after the signal was adopted.
How do you spell SOS in Morse code?
SOS in Morse code is · · · − − − · · · — three short signals (dots), three long signals (dashes), three short signals. It is sent as one continuous sequence without gaps between the letters.
When was SOS first used in an emergency?
The first confirmed use of SOS as a distress signal was by the SS Arapahoe in 1909, after it lost its propeller off Cape Hatteras, USA. The Titanic in 1912 used both the old CQD and the new SOS signal during its sinking.
Is SOS still used today?
Yes — as a visual and acoustic signal. While digital EPIRBs and satellite systems have replaced Morse radio in most maritime use, the visual pattern (3-3-3 flashes or sounds) remains a universally understood distress signal recognised by rescue services worldwide.
How do I send SOS with my phone?
Use your phone's torch (flashlight): 3 short flashes, 3 long flashes, 3 short flashes. Repeat with a pause of a few seconds between each sequence. Most smartphones also have a built-in emergency SOS feature — hold the power button or press it 5 times rapidly to trigger an emergency call.
What's the difference between SOS and Mayday?
SOS is a Morse code signal (visual or radio). Mayday is a spoken voice distress call (from the French "m'aider" — help me), used on radio voice channels. Both signal the same thing — an immediate life-threatening emergency — but on different mediums. Modern distress calls use Mayday; SOS remains valid for visual and sound signalling.