Area Code 42 – Daejeon

Overview of Area Code +82 42

Area code 42 is the National Destination Code (NDC) for Daejeon, a major metropolitan city in South Korea. It is assigned under the country calling code +82 and follows the ITU-T E.164 numbering plan. Daejeon is the fifth-largest city in South Korea and serves as a major administrative, scientific, and technological hub, hosting the headquarters of several government agencies and research institutes, including the Korea Advanced Institute of Science and Technology (KAIST) and the Daejeon Government Complex.

Geographic Coverage and Jurisdiction

This geographic code covers the entire Daejeon Metropolitan City, including its five administrative districts (Gu): Daedeok-gu, Dong-gu, Jung-gu, Seo-gu, and Yuseong-gu. It also serves the surrounding areas that are part of the Daejeon local calling area, such as Gyeryong in South Chungcheong Province and Geumsan County. The code is administered by the Korea Communications Commission (KCC) and allocated to fixed-line operators, including KT, SK Broadband, and LG U+.

Dialing Formats

For local callers within Daejeon, the area code is often omitted when dialing a number within the same NDC. However, when calling from outside the Daejeon area but still within South Korea, the national trunk prefix 0 must be used, followed by the area code and the subscriber number. For example, to call a Daejeon landline from Seoul, you would dial 042-XXX-XXXX (where X represents the 7- to 8-digit subscriber number).

For international callers, the format is +82 42 XXXX XXXX (or +82-42-XXXX-XXXX). The leading '0' of the national prefix is dropped when using the international format. For instance, a Daejeon number such as 042-123-4567 would be dialed as +82 42 123 4567 from overseas.

Number Structure and Overlay

Subscriber numbers in Daejeon are typically 7 to 8 digits long, making the total length of a national significant number (NSN) either 9 or 10 digits (including the area code). No overlay codes have been introduced for Daejeon; the 42 code remains exclusive to this geographic region. However, due to number portability, a number with this prefix may be routed to a mobile or VoIP service, but the geographic association remains for billing and emergency services.

Caller Instructions

• Local callers (within Daejeon): Dial only the subscriber number (e.g., 123-4567).
• National callers (outside Daejeon): Dial 042 followed by the subscriber number (e.g., 042-123-4567).
• International callers: Dial your country's exit code, then 82, then 42, then the subscriber number (e.g., +82 42 123 4567).