Kerrville is about 60 miles northwest of San Antonio and 100 miles west of Austin. Nearly everyone arrives by car — there is no passenger rail and bus service is limited. The drive from San Antonio on I-10 and then TX-16 takes just over an hour and passes through classic Hill Country scenery on the final stretch. From Austin, take US-290 west through Johnson City and Fredericksburg, then TX-16 south into Kerrville; it is about 100 miles and takes around two hours depending on traffic through the Austin suburbs.
The nearest commercial airport with regular service is San Antonio International Airport (SAT). Austin-Bergstrom International (AUS) is another option, especially for travelers coming from the east. Car rental at either airport is straightforward and a car is essential for exploring the Hill Country. There is no meaningful public transport connecting the airports to Kerrville.