Three signals to memorize. That's it. If you only ever learn three things in Morse code, learn these:
The three you have to know
| Signal | Morse | Meaning |
|---|---|---|
| SOS | ... --- ... | Distress — "I need help." Sent as one continuous signal. |
| MAYDAY | -- .- -.-- -.. .- -.-- | The spoken distress call on voice radio; in Morse, SOS is the signal to use |
| HELP | .... . .-.. .--. | Plain-language help, useful once someone is already listening |
How to send it without a radio
With a flashlight
- Short flash = dot (one count).
- Long flash = dash (three counts).
- Pause between flashes in a letter = one count.
- Pause between letters = three counts.
- Pause between words = seven counts.
For SOS: short short short · long long long · short short short. Pause for several seconds. Repeat.
Your phone's flashlight has no SOS mode built in. The iPhone flashlight, for example, only turns on and off and changes brightness, according to Apple's iPhone User Guide. Time the flashes yourself, or use a flasher. On this site, open the translator with SOS loaded and press Flash: the whole screen flashes the pattern, which is visible at night at short range.
With a whistle
Same rhythm: three short blasts, three long, three short. Mountain areas also use the Alpine distress signal: six blasts (or flashes) in a minute, one every ten seconds, then a minute's pause, then repeat. Either way, keep it going.
With sound (banging on pipes, walls, a hull)
Three quick knocks, three slow knocks with longer gaps between them, three quick knocks. Pause. Repeat. Use something hard so each knock is sharp and distinct.
On the ground
Mark "SOS" in large letters with rocks, branches or tracks in snow or sand, as big as you can make it, so it can be seen from the air. The letters work even for someone who knows no Morse.
Useful phrases
If you have the time and energy to send more, these are worth knowing:
- I AM SAFE — .. / .- -- / ... .- ..-. .
- NEED WATER — -. . . -.. / .-- .- - . .-.
- NEED HELP — -. . . -.. / .... . .-.. .--.
- WAIT HERE — .-- .- .. - / .... . .-. .
You can hear any of them in the translator.
What NOT to do
- Don't send a false distress signal as a test. It wastes rescue resources, and in the US federal law (47 U.S.C. § 325) prohibits knowingly transmitting one.
- Don't worry about being slow. A clear, slow SOS is easier to recognise than a fast, ragged one.
- Once help has clearly seen or heard you, stop signalling and follow their instructions.
Practice it before you need it
A rhythm you have practised is easier to produce under stress than one you are reading off a card. Spend two minutes on the keyer tapping out SOS until the pattern is automatic — short-short-short, long-long-long, short-short-short.
Print this
The printable Morse chart is designed to print on one page in either light or dark mode. Keep a copy in a camping kit, glovebox or first-aid bag. International Morse covers 26 letters, 10 digits and the common punctuation marks, and a printed chart is faster than memory when you are under stress.
Frequently asked questions
What is the Morse code for SOS?
Three dots, three dashes, three dots — ... --- ... — sent as one continuous signal with no gaps between the letters.
How do I signal SOS without a radio?
Any on/off signal works: a flashlight (three short, three long, three short flashes), a whistle (same rhythm), or knocking on metal. Phones don't flash SOS by themselves; time the flashes yourself or use a screen flasher such as the one in our translator.
What's the most important emergency Morse signal to know?
SOS. It is the best-known distress signal and works with light, sound or taps. If you learn one thing in Morse, learn this rhythm.