Area Code 403 – Taichung/Changhua

Overview of Area Code +886 403

Area code 403 is a geographic National Destination Code (NDC) assigned to the Taichung and Changhua regions of Taiwan. It is part of the country's E.164 numbering plan, where the full international dialing format is +886 403 XXX XXX (or +886-403-XXX-XXX). This code serves both administrative and commercial needs, covering a densely populated area in central-western Taiwan.

Geographic Coverage and Administrative Jurisdiction

The +886 403 prefix covers the special municipality of Taichung and the surrounding Changhua County. Taichung is Taiwan's second-largest metropolitan area, known for its industrial parks, cultural districts, and as a major transportation hub. Changhua County, to the south of Taichung, is primarily agricultural but also hosts significant manufacturing. The code is allocated for fixed-line (PSTN) services, including traditional copper lines, fiber-optic connections, and some fixed wireless access (FWA) solutions.

Dialing Formats and Caller Instructions

For callers within Taiwan, the local dialing format is 04 03 XXX XXX (the leading 0 is the trunk prefix). For example, a local call to a Taichung number would be dialed as 04 03 123 456. For international callers, the format is +886 403 123 456 (drop the leading 0). When dialing from a mobile phone, it is essential to include the area code even for local calls, as mobile numbers are non-geographic and require the full NDC.

Overlay and Numbering Considerations

Taiwan's numbering plan has implemented overlay codes to address demand. The 403 code is part of the Taichung/Changhua area, which also uses codes such as 4 (for the old Taichung city area) and 48 (for some parts of Changhua). Overlays allow multiple codes to serve the same geographic area, so ten-digit dialing (including the area code) is mandatory for all calls within the region, even for local calls. This ensures that callers reach the correct destination regardless of the specific code assigned to the line.

Technical and Regulatory Notes

From a technical standpoint, the 403 code is used for both residential and business lines. It supports standard telephony services, including fax and dial-up internet (though now largely obsolete). Number portability is available in Taiwan, allowing users to retain their numbers when switching providers, but the geographic code remains tied to the physical location of the line. For VoIP services, users may be assigned a 403 number if they have a fixed-line service in the region, but pure IP-based services often use non-geographic codes. The National Communications Commission (NCC) regulates the allocation and usage of all Taiwanese numbering resources.

Practical Examples

• Local call (within Taichung): 04 03 765 4321
• International call (from abroad): +886 403 765 4321
• Call from a mobile phone in Taiwan: 04 03 765 4321 (must include area code)