Area Code 55 – Antofagasta

Overview of Chile’s +56 55 Geographic Code

The +56 55 country-code and area-code combination is the ITU-T E.164 international dialing prefix for the Antofagasta Region of Chile. This geographic code serves the provincial capital, Antofagasta, along with surrounding coastal and inland communities, including Mejillones, Sierra Gorda, and the mining localities of the Atacama Desert. As a geographic National Destination Code (NDC), 55 is allocated exclusively to fixed-line PSTN and fixed-wireless services within this northern Chilean territory. It does not cover mobile numbers, which use non-geographic 9X prefixes under Chile’s national numbering plan.

Local and International Dialing Formats

Within Chile, calls to another fixed line in the same city can often be made using the eight-digit subscriber number alone, depending on the carrier’s local dialing plan. However, for calls from other regions or from mobile phones, the national trunk prefix 0 must be dialed before the area code: 0 55 XXXX XXXX. For example, a local Antofagasta number might be 2345 6789; from Santiago, you would dial 0 55 2345 6789.

From outside Chile, international callers must replace the trunk prefix with Chile’s country code +56, omitting the leading zero: +56 55 XXXX XXXX. Thus, the same number becomes +56 55 2345 6789 when dialed from abroad. This format is essential for routing calls correctly through international gateways.

Geographic Coverage and Administrative Jurisdiction

The 55 area code is administered under the jurisdiction of the Subsecretaría de Telecomunicaciones (SUBTEL) of Chile. It covers the entire Antofagasta Region (Región de Antofagasta), which is one of Chile’s 16 administrative regions. The region is a major mining hub, hosting large copper and lithium operations, and the code serves both urban centers and remote mining camps. The primary cities and towns under this code include Antofagasta, Mejillones, Taltal, Tocopilla, and Calama, although Calama and its surrounding areas are actually served by the separate code 55? No—Calama is also within the 55 code, as the entire region uses the same NDC. In fact, the region’s largest cities—Antofagasta and Calama—both fall under 55, making it a large geographic area with a single area code.

Overlay and Numbering Considerations

Chile has not implemented overlay codes for fixed-line services in the Antofagasta Region; the 55 code remains the sole geographic code for the region. Subscriber numbers are eight digits long, and the total number of assignable lines is sufficient for the region’s population. Because the code is geographic, number portability allows users to retain their fixed-line number when moving within the same exchange area, but porting to a different geographic code is not permitted. For callers, it is important to note that while mobile numbers in Chile are also eight digits, they always begin with 9 and are reached using the non-geographic prefix +56 9, never with the 55 code.

Caller Instructions

For local callers within Antofagasta, dialing the eight-digit subscriber number may suffice for local calls, but to avoid confusion, it is recommended to dial the full national format: 0 55 XXXX XXXX. For international callers, always use +56 55 followed by the eight-digit number. Remember to drop the trunk prefix 0 when dialing from abroad. This ensures your call routes correctly to any fixed line in the Antofagasta Region.