He was named a coadjutor Bishop to Bishop Ledvina and took up residence in Laredo. After the resignation of Bishop Ledvina in 1949, Bishop Garriga assumed the responsibilities as the third Bishop of Corpus Christi in 1949. During his administration he brought the Jesuit Fathers to the Diocese and had them staff the Corpus Christi Minor Seminary which he built in 1960, the site of the present Corpus Christi Catholic Center. It was also during his tenure that the Shrine of Our Lady of San Juan de Valle was built. He continued to encourage Catholic education throughout the Diocese, a time during which many parochial schools were established. Bishop Adolph Marx was consecrated an Auxiliary Bishop for the Diocese of Corpus Christi and the Benedictine Priory was elevated to an Abbey during the years of his administration.