Area Code 55 – Kamphaeng Phet/Phitsanulok/Sukhothai/Tak/Uttaradit

Geographic Scope and Administrative Coverage

The country calling code +66 is assigned to Thailand under the ITU-T E.164 international numbering plan. The national destination code (NDC) 55 is a geographic area code serving the lower northern region of the country. Specifically, it covers the provinces of Kamphaeng Phet, Phitsanulok, Sukhothai, Tak, and Uttaradit. These provinces are administered under Thailand's central and northern administrative divisions, with Phitsanulok serving as a major economic and transport hub. The code is allocated to fixed-line PSTN services, and numbers under this prefix are typically used for residential, business, and government landlines.

Dialing Formats and Caller Instructions

For domestic callers within Thailand, the trunk prefix '0' is used before the area code. Thus, to call a fixed line in Phitsanulok, you would dial: 0 55 XXX XXX (where X represents the local subscriber number). For international callers, the country code +66 is used, and the leading '0' is omitted. Therefore, the international format becomes: +66 55 XXX XXX. For example, a number in Sukhothai might be dialed as +66 55 612 345 from abroad. Local callers within the same area code can often dial just the seven-digit subscriber number, but this depends on the specific local dialing plan and whether overlay codes are in effect. As of the latest ITU-T recommendations, Thailand has not implemented overlay codes for this region, so the 0 55 prefix remains unique for fixed-line services in the covered provinces.

Geographic vs. Non-Geographic Considerations

It is important to note that the 55 prefix is strictly geographic, meaning the number is tied to a physical location. This contrasts with mobile numbers (which start with 6, 8, or 9) and non-geographic numbers (such as toll-free 1800 or premium 1900). Calls to +66 55 numbers are typically charged at standard domestic or international fixed-line rates, depending on the caller's location and carrier. For businesses, having a local presence in these provinces is facilitated by using a 55 number, which can enhance trust among local customers. However, with the rise of VoIP and cloud-based PBX systems, it is possible to route calls to a 55 number to any destination, but the number itself remains associated with the geographic region for regulatory and emergency services purposes.

Practical Examples and Usage

To illustrate, a business in Kamphaeng Phet might list its contact as +66 55 812 345. A customer calling from Bangkok would dial 0 55 812 345 domestically, while an international client would dial +66 55 812 345. When dialing from a mobile phone in Thailand, it is common to use the international format even for domestic calls, but the domestic format is always accepted. For travelers, it is essential to replace the leading '0' with +66 when storing numbers in international format. The area code 55 is an integral part of Thailand's numbering plan, ensuring efficient routing and clear identification of the geographic origin of fixed-line calls.