SOS in Morse code is ··· ——— ··· — three dots (S), three dashes (O), three dots (S) — transmitted as one continuous sequence without pauses between letters. It is the universally recognized distress signal under the International Convention for the Safety of Life at Sea (SOLAS).
SOS Signal Pattern
· · · — — — · · ·
3 dots · 3 dashes · 3 dots — no pause between letters
Does SOS Stand for Anything?
No — SOS has no official meaning. The letters were chosen in 1905 purely because the pattern (three dots, three dashes, three dots) is simple and impossible to misread. Common backronyms like “Save Our Souls” or “Save Our Ship” were invented after the signal was already adopted. The ITU officially recognized SOS at the first International Radiotelegraph Convention in Berlin in 1906.
History of the SOS Signal
Before SOS, the distress signal was “CQD” — sent by the Marconi company. Germany proposed SOS at the 1906 Berlin conference because the pattern ··· ——— ··· was shorter, simpler, and harder to confuse with routine traffic. The signal became compulsory for ship-to-shore communication in 1908.
The first recorded use of SOS at sea was on August 10, 1909, when the SS Arapahoe signaled for help off the coast of Cape Hatteras, North Carolina. It was famously sent by the RMS Titanic on April 15, 1912.
How to Signal SOS in an Emergency
📻
Radio (Preferred)
Transmit ··· ——— ··· on the international distress frequency 500 kHz (maritime) or 121.5 MHz (aviation). Repeat every few minutes.
🔦
Flashlight / Mirror
Flash 3 short · 3 long — · 3 short. Use any light source — phone screen, signal mirror, or torch. Aim toward rescue aircraft or ships.
🪨
Knock / Tap
Tap 3 short knocks, 3 long, 3 short on any surface — pipe, wall, hull. Used by miners and trapped survivors to signal rescuers.
🔊
Whistle / Horn
Three short blasts, three long blasts, three short blasts. Repeat with a 1-minute pause between repetitions per SOLAS protocol.
FAQs
SOS in Morse code is ··· ——— ··· — three dots, three dashes, three dots. It is transmitted as one unbroken sequence, not as three separate letters, so there are no inter-letter gaps.
No — SOS has no official meaning. The letters were chosen in 1906 because the pattern was simple and unmistakable. “Save Our Souls” and “Save Our Ship” are popular backronyms invented after the signal was adopted.
Tap 3 short (dots), 3 long (dashes), 3 short (dots) with a brief pause between repetitions. Any surface works — pipe, wall, rock. The pattern must be clearly distinct: short taps for dots, long taps for dashes at a 1:3 ratio.