Telephone numbers in Thailand
Thailand's telephone numbering plan in Thailand is managed by the National Broadcasting and Telecommunications Commission (NBTC) in accordance with International Telecommunication Union's (ITU) recommendation E.164. Geographic area codes. Geographic (fixed line) area codes are, excluding the STD prefix one digit in Bangkok and nearby provinces (area code 2) and two digits in all other provinces (area codes 3x, 4x, 5x, and 7x). In Thailand, an area code is usually shared by several provinces and roughly follows provincial borders. Fixed-line subscriber numbers are six digits in Thailand (except Bangkok, Nonthaburi, Pathum Thani, and Samut  Prakan, i.e., area code 2). Prior to 1980, subscriber numbers were six digits in Bangkok, Nonthaburi, Pathum Thani, and Samut Prakan. In 1980, subscriber numbers in these areas were expanded to seven digits in phases to meet new demands. The first digit of a subscriber number is associated with a specific locale within the area code. In Bangkok, Nonthaburi, Pathum Thani, and Samut Prakan, the second digit of a subscriber number identifies the service provider, which is almost always Telephone Organization of Thailand (TOT), as TOT holds a near-monopoly of the Thai fixed-line market. Thus, a full national  number is 9 digits, including the STD prefix 0. When writing a telephone number with the area code, the area code and subscriber number are separated by a hyphen, also in the middle of subscriber number. Examples: Thailand switched to a closed dialing plan in 2021, which means that calling within the area code requires the area code to be dialed. E.g., When calling a number 2134567 in Bangkok (02) from a fixed-line phone: Mobile phone codes and IP telephony. Mobile phone codes are in area codes 8 and 9, and VoIP are in the area code 6, plus  a second digit, resulting in two digits excluding the leading zero. Originally, each mobile phone operator was issued one mobile phone code. Through a series of mergers, there are currently three major mobile phone operators: AIS, True and DTAC. As existing numbers run out, the three mobile phone operators are assigned numbers in code 081, distinguished by the first digit of the subscriber number. A mobile phone number consists of a mobile phone code and a seven-digit subscriber number. Therefore, a mobile phone number is written as 0641163685 Mobile phones in Thailand use 900/1800 MHz for GSM. Domestic roaming  service is available free within Thailand in places where there is only a single transmitter in place due to restrictions. As codes are being exhausted, a new range, 09x, is available for assignment. Despite the length of the code, subscriber numbers are seven digits, resulting in a ten-digit national number including the leading zero. Starting 28 April 2011, the prefix 090 followed by seven digits was available for use. Emergency numbers. Thailand has nearly 100 "hotline" telephone numbers to call for assistance. They include 911 or 191 for emergencies, fire, or unwanted intruding animals; 1699 or 1669 (or 1646  or 1554 in Bangkok) for medical emergencies; tourist police, 1155; car theft, 1192; a taxi refusing a trip, 1584; road accidents, 1146.