San Nicolas comprises 24 barangays with an estimated population of 36,168. 6 of its barangays (25%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| San Agustin | 1,950 | 2 | Crowdsourced signal only (no registered tower) |
| San Baltazar (Pob.) | 558 | 3 | Crowdsourced signal only (no registered tower) |
| San Bartolome (Pob.) | 695 | 4 | Crowdsourced signal only (no registered tower) |
| San Cayetano (Pob.) | 546 | 1 | Crowdsourced signal only (no registered tower) |
| San Eugenio (Pob.) | 607 | 0 | Dead zone: no towers from any source |
| San Fernando (Pob.) | 556 | 1 | Crowdsourced signal only (no registered tower) |
| San Francisco (Pob.) | 1,716 | 37 | Crowdsourced signal only (no registered tower) |
| San Gregorio (Pob.) | 643 | 0 | Dead zone: no towers from any source |
| San Guillermo | 6,482 | 24 | Crowdsourced signal only (no registered tower) |
| San Ildefonso (Pob.) | 1,395 | 7 | Crowdsourced signal only (no registered tower) |
| San Jose (Pob.) | 796 | 1 | Crowdsourced signal only (no registered tower) |
| San Juan Bautista (Pob.) | 2,543 | 1 | Crowdsourced signal only (no registered tower) |
| San Lorenzo | 2,085 | 5 | Crowdsourced signal only (no registered tower) |
| San Lucas (Pob.) | 617 | 0 | Dead zone: no towers from any source |
| San Marcos (Payas) | 4,431 | 4 | Crowdsourced signal only (no registered tower) |
| San Miguel (Pob.) | 1,536 | 1 | Crowdsourced signal only (no registered tower) |
| San Pablo | 1,557 | 3 | Crowdsourced signal only (no registered tower) |
| San Paulo (Pob.) | 350 | 0 | Dead zone: no towers from any source |
| San Pedro (Bingao) | 2,506 | 3 | Crowdsourced signal only (no registered tower) |
| San Rufino (Pob.) | 120 | 0 | Dead zone: no towers from any source |
| San Silvestre (Pob.) | 742 | 6 | Crowdsourced signal only (no registered tower) |
| Santa Asuncion (Samac) | 891 | 1 | Crowdsourced signal only (no registered tower) |
| Santa Cecilia (Barabar) | 1,599 | 0 | Dead zone: no towers from any source |
| Santa Monica (Nagrebcan) | 1,247 | 8 | Crowdsourced signal only (no registered tower) |