SOS is the most recognised signal in the world. Three dots, three dashes, three dots — sent as one continuous unit with no letter gaps. It is the international distress signal, understood in every country, across every medium: radio, light, sound, or tapping.

What is SOS in Morse Code?

S
· · ·
Three dots
O
— — —
Three dashes
S
· · ·
Three dots

In standard Morse code notation: ... --- ...

SOS is technically sent as a single unbroken unit — ···−−−··· — with no gaps between the letters. This makes it instantly recognisable and impossible to confuse with other signals.

Important: SOS is NOT an abbreviation. It does not stand for "Save Our Souls" or "Save Our Ship" — those are popular folk etymologies invented after the signal was already in use. SOS was chosen purely because of how easy it is to send and recognise in Morse code.

Why Was SOS Chosen?

Before SOS, ships used different distress signals — the British used "CQD" (CQ = calling all stations, D = distress). The problem was that CQD was easy to confuse with routine CQ calls in poor conditions.

At the 1906 International Wireless Telegraph Convention in Berlin, delegates needed a new universal standard. SOS won because:

  • Its pattern is perfectly symmetrical — easy to recognise even partially received
  • It cannot be mistaken for any common word or abbreviation
  • Three short, three long, three short is instinctively memorable
  • It can be sent quickly even by an injured or panicking operator

How to Send SOS

🔦

Light (Flashlight or Mirror)

Flash 3 short, 3 long, 3 short. Repeat with a pause between each set. A mirror reflecting sunlight can be seen for miles in daylight.

🔊

Sound (Whistle or Horn)

Blow 3 short blasts, 3 long blasts, 3 short blasts. Pause and repeat. Works with any sound-making device — even banging on a surface.

📻

Radio

On channel 16 VHF (marine) or 121.5 MHz (aviation), send SOS in Morse or say "MAYDAY MAYDAY MAYDAY" followed by your position and situation.

✋

Tapping

Tap on a pipe, wall, or floor: 3 quick taps, 3 slow taps, 3 quick taps. Used by people trapped in collapsed buildings or confined spaces.

🌍

Ground Signal

In open terrain, create SOS using rocks, logs, or any visible material. Use contrast with the background — dark on snow, light on dark ground. Make each letter at least 3 metres tall.

Famous SOS Moments in History

  • RMS Titanic (1912) — Radio operator Jack Phillips sent SOS (and CQD) as the ship sank. The Carpathia received the signal and rescued 705 survivors.
  • SS Eastland (1915) — SOS called within minutes of the ship capsizing in the Chicago River.
  • Apollo 13 (1970) — While not Morse, the crew's distress call followed the same principle of a recognizable, repeatable emergency signal.
  • Chilean miners (2010) — Trapped miners tapped signals through rock using the same principle as Morse — a fixed pattern to signal life.

Try It Yourself

Use our translator to see and hear SOS — or translate any emergency message into Morse code.

Open Morse Code Translator