ONE SIGNAL / NINE MARKS
SOS in Morse Code
Three short signals. Three long signals. Three short signals again. Here is the pattern you can see, hear and remember.
Written in three groups for reading. Played as one continuous signal.
READ THE SIGNAL
Short · long · short.
The first three dots match the letter S, the three dashes match O, and the last three dots match S again. The written grouping ... --- ... makes the pattern easy to read.
The historic distress signal is sent as one continuous group, without the ordinary pauses between separate letters. The audio demo above follows that continuous pattern.
The ITU's maritime history records the 1906 adoption of SOS. An ITU history article explains the continuous group.
TIMING
A dash lasts three dots.
In International Morse code, one dash takes the time of three dots. The gap between marks in a continuous group is one dot unit. That short–long contrast is what makes SOS recognizable by ear or light.
Character patterns and timing checked against ITU-R M.1677-1, International Morse code.
If you need immediate help, contact local emergency services by the most reliable available method. This page is a Morse code reference and audio demonstration.