Area Code 52 – Chiang Mai/Chiang Rai/Lamphun/Mae Hong Son

Geographic Coverage and Administrative Jurisdiction

Area code +66 52 is a geographic National Destination Code (NDC) assigned to the upper northern region of Thailand. It serves the provinces of Chiang Mai, Chiang Rai, Lamphun, and Mae Hong Son. This code is part of the Thai fixed-line telephony network, managed under the National Broadcasting and Telecommunications Commission (NBTC) and operated by licensed fixed-line carriers such as TOT and True Corporation. The code covers both provincial capitals and surrounding districts, providing PSTN services to residential, business, and government subscribers.

Primary Cities and Dialing Formats

The major cities within this code include Chiang Mai (the largest metropolitan area in Northern Thailand), Chiang Rai, Lamphun, and Mae Hong Son town. For local calls within the same area code, subscribers typically dial only the subscriber number, which is 6 to 7 digits long, depending on the exchange. For calls from other provinces within Thailand, callers must dial 0 followed by 52 and the subscriber number (e.g., 0 52 123 456). For international callers, the correct format is +66 52 123 456 (or 0066 52 123 456 when using the international prefix). It is essential to omit the leading trunk prefix '0' when dialing from abroad.

Overlays and Numbering Considerations

Currently, area code 52 does not have an overlay code; it is the sole geographic code for this region. However, due to increasing demand, the NBTC has implemented number pooling and reassignment measures to ensure efficient use of numbering resources. Subscribers may have 7-digit local numbers, but some older exchanges still use 6-digit numbers. When dialing from a mobile phone, it is common to include the area code even for local calls, as mobile networks route based on full national numbers.

Caller Instructions

For local callers within the 52 area: if you are calling a number in the same province and exchange, you may dial only the local number. However, if you are calling from a different province or from a mobile phone, always use the full national format: 0 52 XXX XXXX. For international callers: replace the leading '0' with the country code +66, resulting in +66 52 XXX XXXX. Ensure you have the correct number of digits; if the local number is 6 digits, the international format will be +66 52 XXX XXX. Always confirm the subscriber number length with the called party to avoid misdialing.