What two-letter country-code system is used to create most emoji flags?

Most emoji flags are created from ISO 3166-1 alpha-2 country codes.

A flag emoji usually consists of two Regional Indicator Symbols whose letters correspond to a territory’s two-letter ISO 3166-1 alpha-2 code. For example, the letters for the United Kingdom are represented by regional indicators to produce the United Kingdom flag emoji.

These are not ordinary visible Latin letters in the message. They are special Unicode characters designed to combine in pairs and display as a flag when a platform supports the sequence. If support is absent, a device may show two separate regional-indicator symbols instead.

Not every flag-like emoji is simply a country code. Some represent subdivisions, such as England, Scotland, and Wales, while others use special sequences. The system also reflects ISO’s territory list, which is why geopolitical recognition and emoji availability do not always align perfectly.