Santo Tomas comprises 24 barangays with an estimated population of 34,132. 14 of its barangays (58%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| Ambitacay | 1,057 | 0 | Dead zone: no towers from any source |
| Bail | 2,663 | 0 | Dead zone: no towers from any source |
| Balaoc | 299 | 0 | Dead zone: no towers from any source |
| Balsaan | 397 | 0 | Dead zone: no towers from any source |
| Baybay | 613 | 0 | Dead zone: no towers from any source |
| Cabaruan | 874 | 0 | Dead zone: no towers from any source |
| Casantaan | 1,094 | 1 | Crowdsourced signal only (no registered tower) |
| Casilagan | 3,024 | 0 | Dead zone: no towers from any source |
| Cupang | 917 | 3 | Crowdsourced signal only (no registered tower) |
| Damortis | 1,959 | 3 | Crowdsourced signal only (no registered tower) |
| Fernando | 3,924 | 4 | Crowdsourced signal only (no registered tower) |
| Linong | 234 | 0 | Dead zone: no towers from any source |
| Lomboy | 1,037 | 2 | Crowdsourced signal only (no registered tower) |
| Malabago | 273 | 0 | Dead zone: no towers from any source |
| Namboongan | 1,477 | 7 | Crowdsourced signal only (no registered tower) |
| Namonitan | 3,654 | 2 | Crowdsourced signal only (no registered tower) |
| Narvacan | 355 | 0 | Dead zone: no towers from any source |
| Patac | 3,879 | 8 | Crowdsourced signal only (no registered tower) |
| Poblacion | 1,061 | 0 | Dead zone: no towers from any source |
| Pongpong | 519 | 1 | Crowdsourced signal only (no registered tower) |
| Raois | 705 | 0 | Dead zone: no towers from any source |
| Tococ | 681 | 0 | Dead zone: no towers from any source |
| Tubod | 2,814 | 1 | Crowdsourced signal only (no registered tower) |
| Ubagan | 622 | 0 | Dead zone: no towers from any source |