Radio Thailand World Service began its external service with broadcasts in foreign language under the call sign HSK9 on the 20th of October 1938.

QSL card of Radio Thailand World Service HSK9 of Ashik Eqbal Tokon
On June 24, 1932, the administrative system of Thailand changed from an absolute monarchy to constitutional one. The Public Broadcasting Department (PRD) was set up on May 03, 1933. It was established to carry out the task of informing the people on parliamentary democracy.