|Founded||14 August 2003|
|General Sirichai Distakul (Chairman)|
|Revenue||TH฿ 76.02 billion (2013) |
|TH฿ 11.27 billion (2013) |
|Total assets||TH฿ 175.8 billion (2013) |
|Total equity||TH฿ 41.25 billion (2013) |
CAT Telecom Public Company Limited is the state-owned company that runs Thailand’s international telecommunications infrastructure, including its international gateways, satellite, and submarine cable networks connections. 
Until recently, CAT had a monopoly on international telephony and CDMA mobile telephony. CAT partnered with TOT to provide the GSM mobile service Thai Mobile. In partnership with Hutchison, it provided a CDMA2000 1x mobile service in 25 central provinces and operated its own CDMA2000 1xEV-DO in 51 provinces.
CAT or the Communications Authority of Thailand was established on August 14, 2003 by the government of previous Thai prime minister Thaksin Shinawatra. Plans were under way to privatize a portion of the state enterprise through an IPO in the Stock Exchange of Thailand but these plans were cancelled after the Thaksin government was overthrown by a coup on 19 September 2006. Soon after the coup, the junta of General Surayud Chulanont announced plans to merge CAT with rival state telecom enterprise TOT (Telephone Organization of Thailand).
The junta pointed General Saprang Kalayanamitr as the new chairman of the board of directors for both CAT and TOT. Saprang was accused by the founders of People's Television (PTV), a new satellite television station, of being behind CAT's refusal to grant an internet link from Bangkok to a satellite up-link station in Hong Kong. PTV was established by some previous executives of the Thai Rak Thai party. CAT, however, claimed that it never received PTV's application for internet access.
The junta also cancelled the Thaksin government's telecom excise tax policy. The Thaksin government imposed an excise tax on private fixed and cellular services, and then allowed telecom companies to deduct the amount they paid in excise tax from concession fees to TOT and CAT. The total amount paid by the private telecom firms did not change. The Surayud government's excise tax cancellation meant that TOT and CAT would receive their full concession payments. However, TOT and CAT were then forced to increase their dividends to the Ministry of Finance to account for their increased income.
On 30 November 2013, during the mass protests going on in Bangkok, a group of unidentified protesters infiltrated CAT's headquarter, which hosted its data center, to cut off its electricity. This affected roughly 92,000 clients of the company and resulted in about 300 million baht ($10 million) in lost transactions. Upon the system shut down, internet was inaccessible, phone lines were down, and ATMs were out of service.
CAT includes the following subsidiaries :
- My By CAT (mobile phone operator)
- CAT Internet
MybyCAT services are available in the following provinces:
- Ang Thong Province
- Kanchanaburi Province
- Chanthaburi Province
- Chachoengsao Province
- Chonburi Province
- Trat Province
- Nakhon Nayok Province
- Nakhon Pathom Province
- Nonthaburi Province
- Pathum Thani Province
- Prachuap Khiri Khan Province
- Prachinburi Province
- Phra Nakhon Si Ayutthaya Province
- Phetchaburi Province
- Rayong Province
- Ratchaburi Province
- Lopburi Province
- Samut Prakan Province
- Samut Sakhon Province
- Samut Songkhram Province
- Sa Kaeo Province
- Saraburi Province
- Sing Buri Province
- Suphan Buri Province
- Kalasin Province
- CAT Telecom Financial highlight 2013
- "CAT Telecom moves business focus to IoT digital services - The Nation". The Nation. Retrieved 21 June 2018.
- TeleGeography. "TOT and CAT finally agree Thai Mobile price". www.telegeography.com. Retrieved 2018-02-04.
- TeleGeography. "Hutchison CAT partnership launches CDMA2000 1x national roaming". www.telegeography.com. Retrieved 2018-02-04.
- The Nation, Call for end to policy corruption Archived 2007-03-12 at the Wayback Machine., 16 October 2006
- The Nation, PTV says 'CAT attack' ruined debut Archived 2007-09-29 at the Wayback Machine., 2 March 2007.
- The Nation, Telecom excise tax revoked Archived 2007-10-25 at the Wayback Machine., 24 January 2007
- Tech in Asia. http://www.techinasia.com/thai-protesters-telecom-attacks-cost-country-10-million-damage/
- "Thailand's MVNO market 2014" Yozzo.com
- "MVNO 168 Communications launches in Thailand". Yozzo.com Retrieved 2015-05-17