In this post, you can read about the San Antonio Sacramental Records 1700-1995 that are now online.
This may be old news to you but the Roman Catholic Archdiocese of San Antonio Sacramental Records dating 1700-1995 are have been indexed and are online at Ancestry.
This collection includes the following territory:
If your ancestors lived in any of the above counties then make sure to check out the collection at Ancestry here: https://www.ancestry.com/search/collections/61845/
The only thing is that you do need to be a paying member of theirs in order to access them, but hey it bets going in person.
These records cover many types of church events, such as baptisms, confirmations, marriages, and burials.
Ancestry states that "Records may also include copies of correspondence from outside of the church needed to perform the ceremonies, such as marriage licenses or burial permits. Records in this collection may be written in Latin, Spanish, or English. Most of the records in this collection are handwritten in ledgers, but newer or transcribed records may be typed."
I am personally interested in the records of the Alamo and the San Fernando cathedral. Have fun!