Emergency Signal

SOS in Morse Code

The world's most recognised distress signal — history, audio, and how to send it

SOS in Morse Code
· · · − − − · · ·
... --- ...

Three dots · Three dashes · Three dots — sent as one continuous signal

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How to Signal SOS — 5 Methods

🔦 Flashlight

Flash 3 short, 3 long, 3 short. Pause 1 second between each group of 3. Repeat every 10 seconds.

👋 Tapping

Tap 3 fast, 3 slow, 3 fast on any surface. Short taps = S, long taps = O. Works through walls.

📱 Phone torch

Use your phone's flashlight app or SOS mode. Many phones have a built-in emergency SOS feature.

🪞 Mirror

Reflect sunlight: 3 short flashes, 3 long, 3 short. Effective up to 10 miles in clear conditions.

📣 Sound

Whistle, horn, or shout: 3 short blasts, 3 long, 3 short. Standard maritime distress signal.

🔥 Smoke / Fire

Create 3 smoke signals, pause, 3 more, pause, 3 more. Classic wilderness survival signaling.

What Does SOS Stand For?

Contrary to popular belief, SOS does not stand for anything. It was chosen purely because of its simplicity in Morse code: three dots, three dashes, three dots — easy to remember and impossible to mistake.

However, many backronyms have been attached to it over the years, including "Save Our Souls," "Save Our Ship," and "Send Out Succour." None of these are the actual origin — they came after the signal was already in use.

The signal is officially written as ···−−−··· — a single unbroken sequence with no spaces between the letters S, O, and S. This is what makes it unique in Morse code.

History of the SOS Signal

1906
The International Radio Telegraphic Convention in Berlin adopted SOS as the international distress signal, replacing the earlier CQD signal used by Marconi operators.
1909
The first ship rescue using SOS occurred when the SS Slavonia sent the signal after hitting rocks off the Azores. Two ships received the call and came to the rescue.
1912
The Titanic famously broadcast both CQD and SOS signals. Radio operator Jack Phillips sent the new SOS distress call, making it globally famous overnight.
1927
SOS became mandatory for all ships and maritime vessels under international law, cementing its status as the universal standard.
1999
Maritime Morse code was officially retired with the introduction of the Global Maritime Distress and Safety System (GMDSS). SOS however remains a universal cultural symbol.

SOS vs CQD — What Was Used Before?

Before SOS, Marconi operators used CQD as a distress signal. CQ was the general call for "attention all stations" and D stood for distress. The Titanic's senior wireless operator Jack Phillips initially sent CQD before also sending SOS — saying "Send SOS, it's the new call, and it may be your last chance to send it."

The Pattern: Why 3-3-3?

SOS was chosen specifically because ... --- ... is the easiest Morse pattern to recognise even in poor conditions. Three identical groups, alternating between short and long, stand out immediately from regular traffic.

The full signal lasts just a few seconds, can be sent by anyone with no Morse training, and is immediately recognisable to trained operators.

Frequently Asked Questions

What is SOS in Morse code?

SOS in Morse code is ... --- ... — three dots, three dashes, three dots. It is sent as a single continuous signal without gaps between the letters.

How do you spell SOS in Morse code?

S = ... (dot dot dot), O = --- (dash dash dash), S = ... (dot dot dot). Together: ...---...

What does SOS stand for in Morse code?

SOS does not officially stand for anything. It was chosen for its simplicity — three dots, three dashes, three dots. Popular phrases like "Save Our Souls" were invented after the signal was already in use.

How do you signal SOS with a flashlight?

Flash 3 short blinks, then 3 long blinks, then 3 short blinks. Pause for 1–2 seconds then repeat. Short blinks represent dots (S) and long blinks represent dashes (O).

Is SOS still used today?

While maritime Morse code was retired in 1999, SOS remains a universally recognised distress signal. Modern digital systems replaced it technically, but the SOS pattern with a flashlight or whistle is still a valid survival technique taught worldwide.

What is the Morse code for SOS blinking?

Using a light: 3 short flashes (S), 3 long flashes (O), 3 short flashes (S). Short = about 1 second, long = about 3 seconds. Repeat after a clear pause.