Area Code 55 – Chiayi/Yunlin

Geographic Overview and Administrative Coverage

The +886 55 prefix is the National Destination Code (NDC) assigned to the Chiayi and Yunlin region of Taiwan. This geographic area encompasses Chiayi City, Chiayi County, and Yunlin County, located in the southwestern part of the island. The code covers major urban centers such as Chiayi City, Douliu (the county seat of Yunlin), and numerous smaller towns and rural districts. Administratively, the region is served by Chunghwa Telecom's fixed-line network, although other operators may also provide local loop services.

Dialing Formats and Number Structure

When calling a landline in this region from abroad, the international format is: +886 55 XXXX XXX (or +886 55 XXXX XXX for 7-digit local numbers). The total number of digits after the country code is 9, including the leading '5' of the NDC. For example, a typical number might be +886 55 234 5678. When dialing domestically from another part of Taiwan, callers must use the trunk prefix '0' before the area code: 0 55 XXXX XXX. Within the same local calling area, the area code may be omitted, allowing direct dialing of the 7-digit subscriber number.

Caller Instructions

For international callers: dial your country's exit code (e.g., 011 from the US, 00 from most European countries), followed by Taiwan's country code 886, then the area code 55 (without the leading 0), and the local subscriber number. For example, from the US, you would dial: 011 886 55 234 5678. For local callers within the Chiayi/Yunlin region, simply dial the 7-digit number if you are in the same local area. For callers from other regions in Taiwan, dial 0 55 followed by the subscriber number.

Overlay and Numbering Plan Considerations

Currently, there is no overlay code for this geographic area. The 55 area code is the sole NDC for the region, and no changes are anticipated in the near future. However, as with all Taiwanese geographic codes, the number of digits for subscriber numbers is fixed at 7, and the total length of a domestic number (including trunk prefix) is 10 digits. It is important to note that mobile numbers in Taiwan always begin with 09 and are not tied to geographic regions.

Service and Usage Notes

This area code is used exclusively for fixed-line PSTN services. VoIP services may also be assigned numbers with this prefix, but they are location-independent. When calling from abroad, ensure you have the correct country code and omit any leading zeros. For businesses, having a local presence in Chiayi/Yunlin can be established by obtaining a number with this prefix, which may be used for customer service lines or local offices.