The Vicars Choral of St Nicholas are skilled musicians who sing with all the adult ensembles of the Schola Cantorum, assist in the training of singers, and are remunerated on a semi-professional basis. These posts have their origins in the fifteenth century Collegiate foundation, which included eight singing priests, known as vicars, whose role was to sing the daily services in the church and to train the boy choristers who sang with them. The term vicar (from the Latin vicarius, meaning deputy) was used in many places for those singers who sang the daily services in the place of non-resident clerical dignitaries; in Galway it was also connected with the various parish lands and incomes (vicarages) that gradually accrued to the collegiate establishment.

Currently, there are two Vicars Choral appointed; it is hoped to appoint two more over the coming year (thus covering all four voice parts) an eventually to increase the number to eight, providing a double quartet of singers. These posts are suitable for singers with choral experience and sightreading ability, but also those who would like to develop further their vocal technique and musicianship and to avail of the expertise on offer.