Registration prefixes are issued by the ITU International Telecommunications Union, by virtue of them being used as radio callsigns. It is beyond the scope of this page (for the time being, at least) to comment further on each registration series - for example we could note previously used prefixes, which countries re-use registrations, and so on. We have restricted ourselves to noting the sections of registers which are dedicated to helicopters
| Afghanistan | YA | - |
| Albania | ZA | - |
| Algeria | 7T | - |
| Andorra | C3 | - |
| Angola | D2 | - |
| Anguila | VP-A | - |
| Antigua & Barbuda | V2 | - |
| Argentina | LQ, LV | - |
| Armenia | EK | - |
| Aruba | P4 | - |
| Australia | VH | - |
| Austria | OE | Helicopters were initially in the OE-.X. series but later expanded to OE-X.. as well. OE-BX. is reserved for government departments, principally the police |
| Azerbaijan | 4K | - |
| Bahamas | C6 | - |
| Bahrain | A9C | - |
| Bangladesh | S2 | - |
| Barbados | 8P | - |
| Belarus | EW | - |
| Belgium | OO | - |
| Belize | V3 | - |
| Benin | TY | - |
| Bermuda | VP-B | - |
| Bhutan | A5 | - |
| Bolivia | CP | - |
| Bosnia-Herzegovina | T9 | - |
| Botswana | A2 | - |
| Brazil | PP, PR, PT- | PP Government (national/state), PR/PT all other |
| British Virgin Islands | VP-LV | - |
| Brunei | V8 | - |
| Bulgaria | LZ | - |
| Burkina Faso | XT | - |
| Burundi | 9U | - |
| Cambodia | XU | - |
| Cameroon | TJ | - |
| Canada | C | - |
| Cape Verde | D4 | - |
| Cayman Islands | VP-C | - |
| Central African Republic | TL | - |
| Chad | TT | - |
| Chile | CC | - |
| China | B | - |
| Colombia | HK | - |
| Comoros | D6 | - |
| Congo (Democratic Republic) | 9Q | - |
| Congo (Republic) | TN | - |
| Costa Rica | TI | - |
| Croatia | 9A | - |
| Cuba | CU | - |
| Cyprus | 5B | - |
| Czech Republic | OK | - |
| Denmark | OY | Helicopters in OY-H.. series |
| Djibouti | J2 | - |
| Dominica | J7 | - |
| Dominican Republic | HI | - |
| Ecuador | HC | - |
| Egypt | SU | - |
| El Salvador | YS | - |
| Equatorial Guinea | 3C | - |
| Eritrea | E3 | - |
| Estonia | ES | - |
| Ethiopia | ET | - |
| Falkland Islands | VP-F | - |
| Fiji | DQ | - |
| Finland | OH | Helicopters in OH-H.. series |
| France | F | - |
| French colonies | F-O | - |
| Gabon | TR | - |
| Gambia | C5 | - |
| Georgia | 4L | - |
| Germany | D | Helicopters in D-H.. series |
| Ghana | 9G | - |
| Gibraltar | VP-G | - |
| Greece | SX | Helicopters in SX-H.. series |
| Grenada | J3 | - |
| Guatemala | TG | - |
| Guinea | 3X | - |
| Guinea-Bissau | J5 | - |
| Guyana | 8R | - |
| Haiti | HH | - |
| Honduras | HR | - |
| Hong Kong | B-H | - |
| Hungary | HA | - |
| Iceland | TF | - |
| India | VT | - |
| Indonesia | PK | - |
| Iran | EP | - |
| Iraq | YI | - |
| Ireland | EI | - |
| Israel | 4X | - |
| Italy | I | - |
| Ivory Coast | TU | - |
| Jamaica | 6Y | - |
| Japan | JA | - |
| Jordan | JY | - |
| Kazakhstan | UN | - |
| Kenya | 5Y | - |
| Kiribati | T3 | - |
| Korea, North | P | - |
| Korea, South | HL | HL6101 onwards for piston engined helicopters; HL9101 on for single turbines, HL9201 and 9401 on for multi turbines |
| Kuwait | 9K | - |
| Kyrgyzstan | EX | - |
| Laos | RDPL | - |
| Latvia | YL | Helicopters in YL-H.. series |
| Lebanon | OD | - |
| Lesotho | 7P | - |
| Libya | 5A | - |
| Lithuania | LY | Helicopters in LY-H.. series, one known exception |
| Luxembourg | LX | - |
| Macao | B-M | Helicopters B-MH. series |
| Macedonia | Z3 | - |
| Madagascar | 5R | - |
| Malawi | 7Q | - |
| Malaysia | 9M | - |
| Maldives | 8Q | - |
| Mali | TZ | - |
| Malta | 9H | - |
| Marshall Islands | V7 | - |
| Mauritania | 5T | - |
| Mauritius | 3B | - |
| Mexico | XA to XC | XA commercial, XB private, XC government use |
| Micronesia | V6 | - |
| Moldova | ER | - |
| Monaco | 3A | Currently only using 3A-M.. |
| Mongolia | JU | - |
| Montserrat | VP-LM | - |
| Morocco | CN | - |
| Mozambique | C9 | - |
| Myanmar | XY, XZ | - |
| Namibia | V5 | - |
| Nauru | C2 | - |
| Nepal | 9N | - |
| Netherlands | PH | - |
| Netherlands Antilles | PJ | - |
| New Zealand | ZK | Helicopters in ZK-H.. and ZK-I.. series. Handful of exceptions |
| Nicaragua | YN | - |
| Niger | 5U | - |
| Nigeria | 5N | - |
| Norway | LN | Helicopters in LN-O.. series |
| Oman | A4O | - |
| Pakistan | AP | - |
| Palestine | SU-YA | - |
| Panama | HP | - |
| Papua New Guinea | P2 | - |
| Paraguay | ZP | - |
| Peru | OB | - |
| Philippines | RP | - |
| Poland | SP | - |
| Portugal | CS | Helicopters in the CS-H.. series |
| Qatar | A7 | - |
| Romania | YR | - |
| Russia | RA-, RF | - |
| Rwanda | 9XR | - |
| Samoa | 5W | - |
| San Marino | T7 | - |
| São Tomé e Principé | S9 | - |
| Saudi Arabia | HZ | - |
| Senegal | 6V, 6W | - |
| Serbia | YU | Helicopters in the YU-H.. series |
| Seychelles | S7 | Helicopters in the S7-H.. series |
| Sierra Leone | 9L | - |
| Singapore | 9V | - |
| Slovak Republic | OM | - |
| Slovenia | S5 | - |
| Solomon Islands | H4 | - |
| Somalia | 6O | - |
| South Africa | ZS, ZU | - |
| Spain | EC | - |
| Sri Lanka | 4R | - |
| St Helena & Ascension | VQ-H | - |
| St Kitts & Nevis | V4 | - |
| St Lucia | J6 | - |
| St Vincent & Grenadines | J8 | - |
| Sudan | ST | - |
| Surinam | PZ | - |
| Swaziland | 3D | - |
| Sweden | SE | Helicopters in SE-H.. and SE-J.. series |
| Switzerland & Liechtenstein | HB | Helicopters in the HB-X.. and Z.. series. Historical helicopters in HB-RX. |
| Syria | YK | - |
| Taiwan | B | - |
| Tajikistan | EY | - |
| Tanzania | 5H | - |
| Thailand | HS | - |
| Togo | 5V | - |
| Tonga | A3 | - |
| Trinidad & Tobago | 9Y | - |
| Tunisia | TS | - |
| Turkey | TC | Helicopters in the TC-H.. series |
| Turkmenistan | EZ | - |
| Turks & Caicos Islands | VQ-T | - |
| Tuvalu | T2 | - |
| Uganda | 5X | - |
| Ukraine | UR | - |
| United Arab Emirates | A6 | - |
| United Kingdom | G | - |
| Uruguay | CX | - |
| USA | N | - |
| Uzbekistan | UK | - |
| Vanuatu | YJ | - |
| Vatican City | HV | - |
| Venezuela |
