San Antonio comprises 20 barangays with an estimated population of 38,018. 17 of its barangays (85%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| Arawan | 1,571 | 0 | Dead zone: no towers from any source |
| Bagong Niing | 2,258 | 0 | Dead zone: no towers from any source |
| Balat Atis | 684 | 0 | Dead zone: no towers from any source |
| Briones | 1,589 | 0 | Dead zone: no towers from any source |
| Bulihan | 2,081 | 0 | Dead zone: no towers from any source |
| Buliran | 1,880 | 0 | Dead zone: no towers from any source |
| Callejon | 3,294 | 0 | Dead zone: no towers from any source |
| Corazon | 728 | 0 | Dead zone: no towers from any source |
| Loob | 1,454 | 6 | Crowdsourced signal only (no registered tower) |
| Magsaysay | 1,054 | 0 | Dead zone: no towers from any source |
| Manuel del Valle, Sr. | 842 | 0 | Dead zone: no towers from any source |
| Matipunso | 3,150 | 0 | Dead zone: no towers from any source |
| Niing | 2,355 | 0 | Dead zone: no towers from any source |
| Poblacion | 2,529 | 2 | Crowdsourced signal only (no registered tower) |
| Pulo | 1,776 | 0 | Dead zone: no towers from any source |
| Pury | 2,778 | 1 | Crowdsourced signal only (no registered tower) |
| Sampaga | 2,054 | 0 | Dead zone: no towers from any source |
| Sampaguita | 1,943 | 0 | Dead zone: no towers from any source |
| San Jose | 2,089 | 0 | Dead zone: no towers from any source |
| Sinturisan | 1,909 | 0 | Dead zone: no towers from any source |