B737 Next Generation Undifferentiated
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 9
Time Pressure; Workload
ATC Issue All Types; Conflict Airborne Conflict
Air Traffic Control Issued Advisory / Alert
Airspace Structure
Working ILS final into Runway 13R at SAT. Moderate volume; so the final was out around 15 miles; in the vicinity for 5C1. Aircraft X on roughly a 14 mile modified left base; approximately heading 240; descending from 4;000 to 3;000 feet.  A VFR target pops off of 5C1; climbing rapidly; right into the face of Aircraft X opposite direction. As soon as I noticed; I gave Aircraft X a traffic call and an early turn to final. Before Aircraft X could start his turn; the 2 were 3;200 feet; nose to nose; less than a mile; Aircraft X descending and the VFR climbing. On the scope; it appeared that the 2 aircraft got less than 1/2 mile and 200 feet apart. A traffic alert was issued; and Aircraft X called traffic in sight. The VFR never called SAT ATC; but I continued to observe the aircraft climb northeast and become traffic for 2 other air carriers around 8;800 feet. One GOBBY Departure also needed a traffic alert for the same aircraft. This is far too common of an occurrence. We need to make it compulsory for aircraft departing 5C1; climbing above 2500; to contact SAT Approach Control. Due to the location of 5C1 and its vicinity to the 13R final approach course; to not do so is to jeopardize the safely of aircraft on the instrument approaches into our most commonly used runway.
SAT TRACON Controller reported an unidentified VFR target departed an airport in the vicinity of the final approach course and into confliction with air carrier arrivals.