ICAN/CINA Resolutions 56 and 75 of 1923
| Country | Prefix | Notes |
|---|---|---|
| Germany | D- | Unofficially adopted. Officially allotted per Resolution 809 |
| Afghanistan | Y-A | Officially adopted (Bulletin 12) |
| Albania | B-A | Officially adopted (Bulletin 5) |
| Argentina | Q-A | Officially adopted the marks R-A (Bulletin 7) |
| Austria | A-O | Unofficially adopted A-. Officially allotted OE- per Resolution 941 |
| Bulgaria | Q-B | Officially adopted the marks B-B (Bulletin 5) |
| Chile | B-C | Officially adopted (Bulletin 8) |
| Colombia | T-C | HK- Officially adopted (Resolution 507) |
| Costa Rica | K-C | Officially adopted (Bulletin 5) |
| Dominican Republic | Z-D | Officially adopted (Bulletin 12) |
| Esthonia | W-A | Officially adopted the marks E-A (Bulletin 6) |
| Abyssinia | A-B | Officially adopted (Bulletin 9) |
| Finland | V-F | Officially adopted the marks K-S (Bulletin 6) |
| Lithuania | Z-L | Officially adopted (Bulletin 6) |
| Norway | E-N | Unofficially adopted N (which clashed with the USA). Officially allotted LN- per Resolution 624 |
| Paraguay | W-P | ZP- Officially adopted (Resolution 1019) |
| El Salvador | Y-S | Officially adopted (Bulletin 11) |
| Sweden | S-A | Officially adopted (Bulletin 5) |
| Venezuela | V-E | YV- Officially adopted (Resolution 507) |
| Free City of Danzig | Y-M | Officially adopted (Bulletin 9) |