The original 6th Bombay Infantry was disbanded in 1882. It was raised in 1775 and earned honours for Mysore and Seringapatam. Their uniform originally had black facings. In 1904, Major C W Jacob of the 126th Baluchistan Infantry and later to become Field-Marshal Sir Claude Jacob, raised the 106th Hazara Pioneers with drafts from the 124th Duchess of Connaught's Own Baluchistan Infantry and from his own regiment.
They were a class regiment comprising eight companies of Hazaras. In 1914 they were stationed at Quetta with detachments at Kacha, Kila Saifulla, Manzai, Hirok, Hindubag and Ziarat. They remained in India for most of WW1 but were posted to Mesopotamia in 1918. One company went to France where they were attached to the 107th Pioneers. The authorites found it difficult to place the Hazaras with any other regiment in 1922, so they were formed into their own pioneer regiment after the Madras (1st), Bombay (2nd) and Sikh (3rd) Corps of Pioneers, to be called, at first, the 4th Hazara Pioneers and in 1929 The Corps of Hazara Pioneers. Of all the corps of Pioneers, the Hazaras were the last to be disbanded on 31st March 1933.