Area Code 842 – Coahuila
The phone area code for Coahuila is 842 (international format +52842). Browse local exchange codes (NXX) and carrier assignments below.
📞 Exchange Codes (NXX) for Area Code 842
Select a central office code to view local carrier data and detailed information
📍 Geographic Location of Coahuila
Geographic Overview and Jurisdiction
Area code 842 is a geographic National Destination Code (NDC) assigned to the northern Mexican state of Coahuila de Zaragoza. This numbering area covers the municipalities of San Pedro de las Colonias, Francisco I. Madero (formerly known as Chávez), and Matamoros de la Laguna, which are situated in the southwestern portion of the state, within the Comarca Lagunera region. The administrative seat for this area is the city of San Pedro de las Colonias, a commercial and agricultural hub. The region is served by a mix of fixed-line PSTN and VoIP services, and the code is allocated for local wireline telephony.
Dialing Formats and Call Routing
For callers within Mexico, dialing a number in the 842 area requires the national long-distance prefix '01' followed by the area code and the seven-digit local subscriber number. The complete national format is: 01 842 XXX XXXX. For example, to call a landline in San Pedro from Mexico City, you would dial 01 842 123 4567.
For international callers, the Mexican country code (+52) replaces the national prefix. The international format is: +52 842 XXX XXXX. Thus, a caller from the United States would dial +52 842 123 4567. Note that the leading '0' of the national prefix is not used when dialing from abroad.
Local and Long-Distance Considerations
Within the 842 area, calls between landlines in the same locality may require only the seven-digit local number, depending on the specific local dialing plan. However, since Mexico adopted a unified dialing plan in 2019, all calls, including local ones, can be dialed using the ten-digit format (area code + number). For calls from other area codes in Mexico, the '01' prefix is mandatory. For mobile-to-landline calls, the same national format applies.
No overlay codes have been assigned to this region, so the 842 code remains the sole geographic code for the area. Number portability allows subscribers to retain their numbers when switching between fixed-line operators, but the geographic significance of the code remains unchanged.
Practical Guidance for Callers
- Local callers within the 842 region can dial the seven-digit number directly, but using the full ten-digit format (842 XXX XXXX) is also valid and recommended for consistency.
- National callers from other Mexican states must dial 01 842 XXX XXXX.
- International callers should dial +52 842 XXX XXXX.
Understanding these formats ensures seamless connectivity to businesses and residents in this important agricultural and industrial zone of Coahuila.