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.
Vest-Telemark Billag came into being in 1943 when eleven companies joined forces. Two years later, on August 1, 1972, it merged with Fyresdal-Vrådal-Nissedal Billag and Seljord Automobillag to form Vest-Telemark Bilruter. In January 1974, Reinums Bilruter was also absorbed into the company.