The Diocese of Tuticorin comprises of the major part of the Tuticorin district, nearly half of the Nellai district and a small portion of the Kanyakumari district. The Catholics of this area trace their origin to the time of St. Francis Xavier who spent most of his missionary life in this area.
 
Separated from the diocese of Tiruchirapalli, Tuticorin was created a diocese and entrusted to the diocesan clergy in 1923 by the Apostolic Brief "Quae Catholico Nomini" of Pope Pius XI. It was entrusted to the indigenous clergy with Rt. Rev. Francis Tiburtius Roche, sj, as it's first Bishop. He was also the first Indian Bishop of the Latin Rite.
 
On April 4, 1930 the five parishes of Kooduthalai, Manapad, (Holy Ghost Church), Punnaikayal, Tuticorin (Our Lady of Snows Church) and Vaippar which were till then under the Padroado, were amalgamated into the diocese by virtue of the Papal Bull "Quae ad Spirituale" of Pope Pius XI.