Area Code 21 – Greater Jakarta

Overview of Indonesia's Area Code 21

Area code 21 is the National Destination Code (NDC) assigned to the Greater Jakarta metropolitan area, which includes the Special Capital Region of Jakarta (DKI Jakarta) and its satellite cities: Bogor, Depok, Tangerang, and Bekasi. This region is the political, economic, and cultural heart of Indonesia, hosting the nation's capital and the majority of its business headquarters. As a geographic code, 21 is used for fixed-line (PSTN) and fixed-wireless services within this densely populated area.

Dialing Formats

For domestic callers outside the 21 area, the correct format is: 0-21-XXXXXXX (where XXXXXXX is the 7- or 8-digit subscriber number). For callers within the same area code, local dialing typically omits the trunk prefix and area code: XXXXXXX. International callers should dial +62-21-XXXXXXX, replacing the leading '0' with the country code. For example, a Jakarta landline number might be +62 21 55501234.

Geographic Coverage and Numbering

The 21 code covers an area of approximately 6,400 square kilometers and serves over 30 million inhabitants. Subscriber numbers in Jakarta can be 7 or 8 digits long, depending on the operator and service type. To meet growing demand, an overlay plan has been implemented, allowing multiple numbering pools within the same geographic region without changing the area code. This means that new fixed-line subscribers may receive numbers that differ in length from older ones, but all share the 21 NDC.

Caller Instructions

Local callers within Jakarta can dial the 7- or 8-digit number directly. If calling from outside the 21 area but still within Indonesia, you must dial the trunk prefix '0' followed by '21' and the subscriber number. For example, from Bandung, you would dial 021-55501234. International callers must use the country code +62 and drop the leading '0', so the same number becomes +62 21 55501234. It is essential to verify the exact number of digits, as some older lines have 7 digits while newer ones have 8.

Important Considerations

While 21 is primarily a geographic code, some VoIP and fixed-wireless operators may use it for non-geographic services, but this is less common. Mobile numbers in Indonesia always begin with '08' and are not tied to area codes. When dialing from abroad, ensure you use the correct international exit code (e.g., 011 from the US) before the country code. For travelers, local SIM cards are widely used for mobile communication, but for business or residential landlines, understanding the 21 dialing format is crucial for reliable connectivity.