In 1943 11 companies merged to form Vest-Telemark Billag, and on 1 August 1972 it merged with Fyresdal-Vrådal-Nissedal Billag and Seljord Automobillag to create Vest-Telemark Bilruter. In January 1974 also a part of Reinums Bilruter was taken over.
The formation of Vest-Telemark Billag occurred in 1943 when eleven companies merged. Two years later, on August 1, 1972, it joined forces with Fyresdal-Vrådal-Nissedal Billag and Seljord Automobillag to create Vest-Telemark Bilruter. In January 1974, Reinums Bilruter was also added to the company.