In 1880, Chao Muen Samuhjairaj submitted a letter to propose the opening of a post office in Thailand to King Chulalongkorn (King Rama V). His Majesty agreed with the proposal and appointed His Royal Highness Somdetch Phra Chao Nong Ya Tho Chao Fa Bhanurangsi Swangwong Krom Luang Bhanuphandhuwong Wordej as the first Director-General of the Post Department in view of His Royal Highness’ experience in the distribution of the daily newspaper called “Khow Ratchakarn”, meaning the public service news. After well planned and prepared for the opening of the post office, HRH Bhanurangsi Swangwong proclaimed the inauguration of postal service on trial by accepting letters and books in both Phranakorn and Thonburi sides on 4th August 1883. The first post office was located in a large building by the Chaophraya river, at the northern side of Ong-Ang canal (now replaced by the bridge running parallel with the Memorial Bridge) and was also served as the Phranakorn district post office. The building was called “Praisaneeyakarn”, meaning the postal building.
In 1898, the Minister of Public Works proposed that the activities of the Post Department and the Telegraph Department, which was founded earlier, were in the communication field, therefore, they should be merged as one unit to facilitate convenient operation. King Chulalongkorn agreed with the proposal and ordered the merger of the two government entities as “The Post and Telegraph Department”. The Post and Telegraph Department’s location was later moved to Charoenkrung road and has become widely known as “The Central Post Office.” Since postal service was a public service, it was prerequisite to determine regulations by which the public and postal officials would abide. Therefore, after a two-year postal operation, the government enacted in 1885 the Postal Act which was later abolished by the Postal Royal Enactment in 1897. The latter regulation was effective until it was amended and the Postal Act 1934 was enacted. The enforcement of the Post Act 1934 was supervised by the Commerce Minister. (Today, it is supervised by the Information and Communication Technology Minister and the Act has been effective to the present.)
The Communications Authority of Thailand (CAT) was established on 25th February 1977 as a state-owned enterprise in accordance with the Communications Authority of Thailand Act 1976. Since her establishment, all aspects of postal operations including service provisions previously undertaken by the Post and Telegraph Department were transferred to the CAT and she has been responsible for the development of the postal service ever since. During the early days, the office of the CAT was at the Central Post Office and was later moved to Chaeng Watthana Road. The CAT had developed postal infrastructure and her operating system constantly and become one the leading state-owned enterprise in the Kingdom, renowned for her capability and service quality that had continually been kept up to the international standards.
In relation to the state enterprise reform policy of the government, which intends to increase the efficiency of the public service sector to correspond with that of the private sector, the CAT is one among other state-owned enterprises that are deemed to be part of this reform policy. The Cabinet approved the transformation of the CAT on 8th July 2003 in accordance with the Telecommunication Development Master Plan and the Corporatization Act 1999. The CAT was separated and corporatized into 2 distinct business entities on 14th August 2003, which are the CAT Telecom Public Company Limited and the Thailand Post Company Limited.