Telephone services in Catalonia were introduced in the late 19th century. At the time there were two telephone companies in Catalonia: Companyia Telefònica del Vallès and Companyia Peninsular de Telèfons.
The Commonwealth of Catalonia, started the process of linking the majority of Catalan towns by telephone. After Spanish prime minister Miguel Primo de Rivera abolished the Commonwealth, work on the Catalan intercity telephone network was interrupted. It would not be completed until after the Spanish Civil War.
The Telephone Department of the Commonwealth of Catalonia is founded on 2 March 1915. The Telephone Department is charged with bringing telephone service to all parts of Catalonia. On 20 July, the Commonwealth signs an agreement with the Companyia Peninsular de Telèfons, allowing the Commonwealth to lay down those lines it sees fit to create, without prejudice to the rights of the company. A royal decree on 9 September authorizes the Commonwealth to install and operate the remaining Catalan telephone network to form "an intercity telephone network capable of joining some or all of the people of the four provinces of the Catalan Commonwealth".
In 1916, the Barcelona Technology Agency of the Telephone Department of the Commonwealth is formed. On 1 July, the phonebox at Mollerussa becomes operational and on 8 August the phonebox at Lleida becomes operational. On 3 February 1924, the first automatic telephone exchange in Spain is inaugurated in Balaguer.
On 19 April 1924, The Spanish National Telephone Company is constituted and in 1925, the Commonwealth's telephone network becomes part of the Spanish National Telephone Company. Telephone service is instituted between Spain and the United States in 1928. Following the Spanish Civil War, the era of State control of the telephone service begins.
The entry of Spain to the European Union leads to the promulgation of the Law on the Regulation of the Telecommunications Industry, which regulates the new certification system for telephone companies and allows for the entry of other network operators.