Perfect implementations

The ISO 3166-1 alpha-2 codes are used in the following standards:

Imperfect implementations

Starting in 1985, ISO 3166-1 alpha-2 codes have been used in the Domain Name System as country code top-level domains (ccTLDs). The Internet Assigned Numbers Authority currently assigns the ccTLDs mostly following the alpha-2 codes, but with a few exceptions.^[8] For example, the United Kingdom, whose alpha-2 code is GB, uses .uk instead of .gb as its ccTLD, as UK is currently exceptionally reserved in ISO 3166-1 on the request of the United Kingdom.

The WIPO coding standard ST.3 is based on ISO 3166-1 alpha-2 codes, but includes a number of additional codes for international intellectual property organizations, which are currently reserved and not used at the present stage in ISO 3166-1.^[9]

The European Commission generally uses ISO 3166-1 alpha-2 codes with two exceptions: EL (not GR) is used to represent Greece, and UK (not GB) is used to represent the United Kingdom.^[10][11] This notwithstanding, the Official Journal of the European Communities specified that GR and GB be used to represent Greece and United Kingdom respectively.^[12] For VAT administration purposes, the European Commission uses EL and GB for Greece and the United Kingdom respectively.

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.^[13]

IETF language tags (conforming to the BCP 47 standard track and maintained in an IANA registry) are also partially derived from ISO 3166-1 alpha-2 codes (for the region subtags). The full list of ISO 3166-1 codes assigned to countries and territories are usable as region subtags. Also, the "exceptionally reserved" alpha-2 codes defined in ISO 3166-1 (with the exception of UK) are also usable as region subtags for language tags. However, newer stability policies (agreed with ISO) have been implemented to avoid deleting subtags that have been withdrawn in ISO 3166-1; instead they are kept and aliased to the new preferred subtags, or kept as subtags grouping several countries. Some other region grouping subtags are derived from other standards. Under the newer stability policies, old assigned codes that have been withdrawn from ISO 3166-1 should no longer be reassigned to another country or territory (as has occurred in the past for "CS").

Decoding table

The following is a colour-coded decoding table of all ISO 3166-1 alpha-2 codes.

Officially assigned code elements

The following is a complete list of the 249 current officially assigned ISO 3166-1 alpha-2 codes, with the following columns:^[1]

• Code: ISO 3166-1 alpha-2 code, pointing to its ISO 3166-2 article
• Country name: English short name officially used by the ISO 3166 Maintenance Agency (ISO 3166/MA)
• Year: Year when alpha-2 code was first officially assigned (1974, first edition of ISO 3166)
• ccTLD: Corresponding country code top-level domain (some are inactive); exceptions where another ccTLD is assigned for the country are shown in parentheses
• Notes: Any unofficial notes

User-assigned code elements

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-2 codes can be user-assigned: AA, QM to QZ, XA to XZ, and ZZ.^[21] For example:

• The International Standard Recording Code (ISRC) uses QM as a second country code for the United States, as it ran out of three-character registrant codes within the US prefix. It also uses ZZ for some registrants assigned directly.^[22]
• The Unicode Common Locale Data Repository (CLDR) assigns QO to represent Outlying Oceania (a multi-territory region containing Antarctica, Bouvet Island, the Cocos (Keeling) Islands, Christmas Island, South Georgia and the South Sandwich Islands, Heard Island and McDonald Islands, the British Indian Ocean Territory, the French Southern Territories, and the United States Minor Outlying Islands), and ZZ to represent "Unknown or Invalid Territory". Before the adoption of the macroregion code EU by ISO, CLDR also used QU to represent the European Union.^[23]
• The code QZ is being used by the World Intellectual Property Organization (WIPO) as an indicator for the Community Plant Variety Office.
• The code XA is being used by Switzerland^[24] as a country code for the Canary Islands, although IC is already reserved for that purpose.
• The codes XA and XO are being used by Russia^[25] to represent Abkhazia and South Ossetia respectively.
• The code XI is being used by the UK Government,^[26] as an EORI number country code prefix for Northern Ireland, and the members of European union for European Union value added tax reports with trade with Northern Ireland.^[27]
• The code XK is being used by the European Commission^[28] the IMF, and SWIFT,^[29] the CLDR, and other organizations as a temporary country code for Kosovo.^[30]
• The code XN is being used by WIPO as an indicator for the Nordic Patent Institute, an international organization common to Denmark, Iceland, Norway and Sweden.^[31]
• The code XU is being used by WIPO as an indicator for the International Union for the Protection of New Varieties of Plants.
• The code XV is being used by WIPO as an indicator for the Visegrad Patent Institute.
• The code XX is being used by WIPO as an indicator for unknown states, other entities or organizations.
• UN/LOCODE assigns XZ to represent installations in international waters.^[7]

Furthermore, the code element OO is designated as an escape code if the number of regular user-assigned code elements is not sufficient.^[32]

Reserved code elements

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-2 codes can be divided into the following four categories: exceptional reservations, transitional reservations, indeterminate reservations, and codes currently agreed not to use.