ISO 3166-1 alpha-3 codes are three-letter country codes defined in ISO 3166-1, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), to represent countries, dependent territories, and special areas of geographical interest. They allow a better visual association between the codes and the country names than the two-letter alpha-2 codes (the third set of codes is numeric and hence offers no visual association).[1] They were first included as part of the ISO 3166 standard in its first edition in 1974.
The ISO 3166-1 alpha-3 codes are used most prominently in ISO/IEC 7501-1 for machine-readable passports, as standardized by the International Civil Aviation Organization, with a number of additional codes for special passports; some of these codes are currently reserved and not used at the present stage in ISO 3166-1.[2]
The United Nations uses a combination of ISO 3166-1 alpha-2 and alpha-3 codes, along with codes that pre-date the creation of ISO 3166, for international vehicle registration codes, which are codes used to identify the issuing country of a vehicle registration plate; some of these codes are currently indeterminately reserved in ISO 3166-1.[3]
The following is a complete list of the current officially assigned ISO 3166-1 alpha-3 codes,[4] using a title case version of the English short names officially defined by the ISO 3166 Maintenance Agency (ISO 3166/MA):
User-assigned code elements are codes at the disposal of users who need to add further names of countries, territories, or other geographical entities to their in-house application of ISO 3166-1, and the ISO 3166/MA will never use these codes in the updating process of the standard. The following alpha-3 codes can be user-assigned: AAA to AAZ, QMA to QZZ, XAA to XZZ, and ZZA to ZZZ.[5]
The following codes are used in ISO/IEC 7501-1 for special machine-readable passports:[2]
NATO STANAG 1059 INT is built upon ISO alpha-3 codes, but also defines alpha-2 codes incompatible with ISO 3166-1. It introduces several private use codes for fictional countries and organizational entities:
NATO also continues to use reserved codes for continents:
Reserved code elements are codes which have become obsolete, or are required in order to enable a particular user application of the standard but do not qualify for inclusion in ISO 3166-1. To avoid transitional application problems and to aid users who require specific additional code elements for the functioning of their coding systems, the ISO 3166/MA, when justified, reserves these codes which it undertakes not to use for other than specified purposes during a limited or indeterminate period of time. The reserved alpha-3 codes can be divided into the following four categories: exceptional reservations, transitional reservations, indeterminate reservations, and codes currently agreed not to use.
Exceptionally reserved code elements are codes reserved at the request of national ISO member bodies, governments and international organizations, which are required in order to support a particular application, as specified by the requesting body and limited to such use; any further use of such code elements is subject to approval by the ISO 3166/MA. The following alpha-3 codes are currently exceptionally reserved:
The following alpha-3 codes were previously exceptionally reserved, but are now officially assigned:
Transitional reserved code elements are codes reserved after their deletion from ISO 3166-1. These codes may be used only during a transitional period of at least five years while new code elements that may have replaced them are taken into use. These codes may be reassigned by the ISO 3166/MA after the expiration of the transitional period. The following alpha-3 codes are currently transitionally reserved:
Indeterminately reserved code elements are codes used to designate road vehicles under the 1949 and 1968 United Nations Conventions on Road Traffic but differing from those contained in ISO 3166-1. These code elements are expected eventually to be either eliminated or replaced by code elements within ISO 3166-1. In the meantime, the ISO 3166/MA has reserved such code elements for an indeterminate period. Any use beyond the application of the two Conventions is discouraged and will not be approved by the ISO 3166/MA. Moreover, these codes may be reassigned by the ISO 3166/MA at any time. The following alpha-3 codes are currently indeterminately reserved:
The following alpha-3 code was previously indeterminately reserved, but has been reassigned to another country as its official code:
In addition, the ISO 3166/MA will not use the following alpha-3 codes at the present stage, as they are used in ISO/IEC 7501-1 for special machine-readable passports:
Besides the codes currently transitionally reserved and two other codes currently exceptionally reserved (FXX for France, Metropolitan and SUN for USSR), the following alpha-3 codes have also been deleted from ISO 3166-1:[8]