SOS in Morse Code

In a real emergency: call your local emergency number first — 911 in the US and Canada, 112 across Europe and much of the world, 999 in the UK, or your local equivalent — or use an official distress channel such as a marine radio or a registered distress beacon. This page is an educational signalling tool for learning and practising Morse: it is not a replacement for emergency services or proper safety equipment. Morse is the backup for when normal channels fail — not a substitute for them.

What is SOS?

SOS is the international Morse code distress signal: a call for help used when lives are in grave and imminent danger. It is simply the letters S (...) and O (---) arranged as ... --- ... — but radio operators traditionally send it as one continuous flowing signal, with no letter gaps, so it has a rhythm all of its own: short-short-short, long-long-long, short-short-short. That unmistakable beat is the whole point: it can be recognised through static, by a half-asleep operator, or tapped out by someone too weak to send anything else.

Contrary to popular belief, SOS does not stand for anything. "Save Our Souls" and "Save Our Ship" are backronyms — meanings invented afterwards because they are easy to remember. The signal was chosen for its sound, not its initials.

The story of SOS

Born in Germany, adopted by the world

Before SOS, ships used various distress calls, including Marconi's CQD. Germany proposed the ... --- ... signal in its radio regulations of 1905, and the International Radiotelegraph Convention in Berlin adopted it in 1906. It became the worldwide standard on 1 July 1908.

The Titanic sent SOS — and CQD

When the Titanic struck an iceberg in April 1912, her wireless operators Jack Phillips and Harold Bride sent the older CQD first, then — half-joking that it might be their only chance to try the new one — sent SOS as well. The disaster proved the value of a single universal signal and of round-the-clock radio watches, and SOS reigned at sea for the rest of the century.

The Titanic’s story is told in full among the famous Morse code messages on our blog — together with the first telegraph message of 1844 and the prisoner who blinked TORTURE on live TV.

Retired at sea, alive everywhere else

On 1 February 1999, the satellite-based Global Maritime Distress and Safety System (GMDSS) officially replaced Morse distress calls at sea. But SOS never left the public mind: it is still taught in survival training (as part of the "rule of three" — three of anything signals distress), flashed with torches and mirrors, and understood in every country on Earth.

How to signal SOS

• By sound: three short beeps or taps, three long ones, three short ones. Pause, then repeat.
• By light: the same pattern with a flashlight — three quick flashes, three slow flashes, three quick flashes. The signal lamp at the top of this page shows you exactly how it looks.
• By radio: send ...---... as one flowing signal, repeated, followed by your location if you can.
• In the wild: three whistle blasts, three fires in a triangle, or three of any signal, repeated — rescuers worldwide are trained to look for groups of three.

Want to send more than SOS? Write your whole message with the Morse code translator, or learn the full alphabet.