ISO 3166-2:ST is the entry for São Tomé and Príncipe (written without diacritics in the standard) in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions (e.g., provinces or states) of all countries coded in ISO 3166-1.
Currently for São Tomé and Príncipe, ISO 3166-2 codes are defined for 1 autonomous region and 6 districts. Each code consists of two parts, separated by a hyphen. The first part is ST, the ISO 3166-1 alpha-2 code of São Tomé and Príncipe. The second part is a letter for an autonomous region or two digits for a district.