As adopted at the first meeting of ICAN/CINA 13 October 1919
| Country | Prefix | |
|---|---|---|
| United States of America | N | |
| British Empire | G | |
| France | F | |
| Italy | I | |
| Japan | J | |
| Hedjaz | A-H | |
| Nicaragua | A-N | |
| Bolivia | C-B | |
| Cuba | C-C | |
| Portugal | C-P | |
| Roumania | C-R | |
| Uruguay | C-U | |
| Ecuador | E-E | |
| Haiti | H-H | |
| Siam | H-S | |
| Czechoslovakia | L-B | |
| Guatemala | L-G | |
| Liberia | L-L | |
| Belgium | O-B | |
| Peru | O-P | |
| Brazil | P-B | |
| Poland | P-P | |
| Greece | S-G | |
| Panama | S-P | |
| China | X-C | |
| Honduras | X-H | |
| Serbia-Croatia-Slavonia | X-S |