The ICAO Phonetic Alphabet
The ICAO phonetic alphabet is the official international aviation spelling standard — and it's identical to the NATO phonetic alphabet. Here's everything you need to know about the ICAO version specifically.
ICAO vs NATO: These are the same alphabet. ICAO (International Civil Aviation Organization) adopted it in 1956 for aviation. NATO adopted the same words simultaneously for military use. The words are identical — only the organization that mandates it differs.
The ICAO/NATO Phonetic Alphabet — Complete Table
| Letter | ICAO Code Word | Pronunciation | Morse |
|---|---|---|---|
| A | Alfa | Alfa | • — |
| B | Bravo | Bravo | — • • • |
| C | Charlie | Charlie | — • — • |
| D | Delta | Delta | — • • |
| E | Echo | Echo | • |
| F | Foxtrot | Foxtrot | • • — • |
| G | Golf | Golf | — — • |
| H | Hotel | Hotel | • • • • |
| I | India | India | • • |
| J | Juliett | Juliett | • — — — |
| K | Kilo | Kilo | — • — |
| L | Lima | Lima | • — • • |
| M | Mike | Mike | — — |
| N | November | November | — • |
| O | Oscar | Oscar | — — — |
| P | Papa | Papa | • — — • |
| Q | Quebec | Quebec | — — • — |
| R | Romeo | Romeo | • — • |
| S | Sierra | Sierra | • • • |
| T | Tango | Tango | — |
| U | Uniform | Uniform | • • — |
| V | Victor | Victor | • • • — |
| W | Whiskey | Whiskey | • — — |
| X | X-ray | X ray | — • • — |
| Y | Yankee | Yankee | — • — — |
| Z | Zulu | Zulu | — — • • |
ICAO Number Pronunciation
ICAO specifies exact pronunciation for numbers — different from everyday speech to prevent misunderstanding over radio in international contexts.
| Digit | ICAO Spoken Form | Why Different? |
|---|---|---|
| 3 | TREE | Avoids confusion with "free" over static |
| 4 | FOW-ER | Clearer across language barriers |
| 5 | FIFE | Avoids confusion with "fire" |
| 9 | NIN-ER | Avoids confusion with German "nein" (no) |
| . | DAY-SEE-MAL | Unambiguous decimal point for frequencies |
Where ICAO Alphabet Is Mandatory
All International Aviation
Every pilot communicating with ATC across national borders must use ICAO spelling. Codified in ICAO Annex 10, Volume II.
Air Traffic Control (ATC)
Controllers worldwide use ICAO spelling for aircraft callsigns, waypoints, airports, and instructions.
METAR & TAF Weather Reports
Aviation weather uses ICAO station identifiers (4-letter codes like KDEN, EGLL) pronounced using the ICAO alphabet.
Flight Plans
All international flight plan submissions use ICAO identifiers, airport codes, and waypoints spelled using the ICAO alphabet.
Maritime Communication
The IMO adopted the ICAO alphabet for ship radio communication, making it the standard for both air and sea.