We do not have enough data on this route to provide a reliable graph showing how many days before departure it is the best to book.
However, usually the closer it is to the departure, the more expensive the tickets are.
There is no direct flight on the route from Salt Lake City Intl Airport to San Antonio Intl Airport
The shortest flights with a change last approx. 5h 5min.
Salt Lake City (UT) San Antonio (TX)