The Bexar County Jail occasionally houses inmates at other jail facilities. The ones used most often are Frio County, Zavala County and Guadalupe County. If you want to send a letter to an inmate that is housed at another jail you will need to call that jail to get their mailing instructions and address.
The phone numbers for the different jails are:
Frio County – 830-334-3311
Guadalupe County – 830-379-1224
Zavala County – 830-374-3615