Walk when and where you can. It’s free and easy (maybe less so at the end of the day) and you don’t have to wait around for a ride. If you can walk to the convention center you’ll save time and money on parking.
Use Google Maps
Google Maps gives walking directions, just select the walking man icon rather than the car. It’ll keep you on sidewalks and crosswalks.
Wait Wait Wait
The crosswalk signals in San Antonio closer to the convention center are infamous for their “Wait Wait Wait” dialog.
Beep vs Wait
You’ll need to push the cross button to get a pedestrian signal. The crosswalks will beep if no one has pushed the button, and will say “Wait” over and over if someone has pushed it.
You can call a traditional taxi if you like (just Google “San Antonio taxi”), but if you haven’t yet check out Uber and/or Lyft. Both operate in the city and can pick up and drop off at the airport. They typically run cheaper than a taxi and are a lot more convenient with their smartphone apps. If you have multiple people riding it can get even cheaper per person, and larger vehicles are available for larger groups.