SOS in Morse Code
The most important signal in Morse code — the international call for help:
What SOS Means
SOS is the international distress signal: it means "we need rescue, now". On paper it is written as the letters S-O-S, but on the key it is sent as one single flowing signal — three dots, three dashes, three dots, with no pauses between the letters: ...---.... That unbroken rhythm is the point. In noise, static and panic, no other pattern sounds like it.
Contrary to popular belief, SOS does not stand for "Save Our Souls" or "Save Our Ship". Those phrases were invented later as easy ways to remember the letters. The signal was chosen for purely practical reasons: on a telegraph or radio key it is the simplest pattern that can never be confused with anything else.
A Short History
Germany first put the signal into its radio regulations in 1905, and in 1906 the International Radiotelegraph Convention adopted ... --- ... as the worldwide distress call; it came into force in 1908. Before SOS, ships used the older CQD call, which was slower and easier to mishear.
SOS became famous in the age of the great ocean liners — wireless operators on sinking ships tapped it out while their vessels went down, and rescue ships steamed toward the signal. It remained the maritime distress call for most of the twentieth century, until satellite-based systems (GMDSS) officially replaced Morse for shipping in 1999. Even so, SOS never disappeared: it is still recognised everywhere, by everyone, instantly — which is exactly why it is worth knowing.
How to Send SOS
By sound
On a whistle, horn or radio key: three short blasts, three long blasts (each about three times as long), three short blasts. Pause for a few seconds, then repeat. Press the Hear SOS button above to learn the rhythm.
By light
With a torch or phone light at night: three quick flashes, three long flashes, three quick flashes — the same rhythm as the sound. Repeat it toward anyone who might see: a road, a boat, a window, the sky if aircraft are searching. Our translator's light flasher shows the pattern on screen.
By tapping
Trapped or unable to shout? Tap the pattern on a pipe, wall or floor — short-short-short, long-long-long, short-short-short. Rescuers listening for survivors know this rhythm.
When to Use It
SOS is for genuine emergencies only: a life at risk, a boat in trouble, a person lost or trapped. It is not a toy signal — aircraft and rescue services still respond to it. If you can make a normal emergency call, do that first; use SOS when voice communication is impossible or has failed. Learn the full alphabet on our Morse Code Alphabet chart, and practise any message with the Morse Code Translator.