Area Code 728 – Lerma/Santa Maria Atarasquillo, MEX

Overview of Area Code 728

Area code 728 is a geographic numbering plan area within the Mexican state of Mexico (Estado de México), assigned to the municipalities of Lerma and Santa María Atarasquillo, along with their surrounding localities. This region forms part of the greater Toluca metropolitan area and is situated approximately 50 kilometers west of Mexico City. The code serves both residential and business lines, including fixed-line PSTN services, and is administered under the country code +52.

Geographic Coverage and Administrative Jurisdiction

The 728 area code covers a mix of urban and semi-rural zones. Key localities include Lerma de Villada (the municipal seat), Santa María Atarasquillo, San Miguel Ameyalco, and other communities within the Lerma Municipality. The region is known for its industrial parks and commercial corridors, as well as its proximity to the Toluca–Mexico City highway, making it a hub for logistics and manufacturing. The administrative jurisdiction falls under the Secretariat of Infrastructure, Communications and Transportation (SICT) of Mexico, which oversees the national numbering plan.

Dialing Formats and Caller Instructions

For local callers within the 728 area code, it is necessary to dial the 10-digit national number, which includes the area code followed by the 7-digit local subscriber number. For example, to call a fixed line in Lerma, you would dial 728 123 4567 (where 123 4567 is the local number). For international callers, the full international format must be used: +52 728 123 4567. When calling from a mobile phone within Mexico, the same national format applies, but long-distance charges may apply if the caller is outside the 728 area. It is important to note that Mexico has implemented an overlay for some regions, but as of now, 728 is the sole area code for this geographic area, and no additional overlay codes have been assigned.

Technical Considerations

From a technical standpoint, area code 728 is a geographic code, meaning that numbers are tied to a physical location. However, with the advent of number portability, subscribers may retain their 728 numbers even if they move to a different region, although this is less common for fixed lines. The numbering plan follows ITU-T E.164 recommendations, and the maximum number length is 13 digits when including the +52 country code. For VoIP services, users may be assigned a 728 number, but routing is based on the number's portability status rather than the physical location of the VoIP adapter.

Practical Examples

• Local call (within 728): Dial 728 456 7890
• National call (from other area codes in Mexico): Dial 01 728 456 7890 (long-distance prefix 01 is used for fixed-line calls)
• International call (from abroad): Dial +52 728 456 7890

When calling from a mobile phone, the national format is typically 10 digits (e.g., 728 456 7890), but if you are calling from a mobile to a fixed line, you may need to include the long-distance prefix 01 depending on your carrier's dialing plan. For international callers, always use the plus sign and country code to ensure proper routing.