San Nicolas comprises 33 barangays with an estimated population of 40,753. 25 of its barangays (76%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| Bensican | 480 | 0 | Dead zone: no towers from any source |
| Cabitnongan | 753 | 0 | Dead zone: no towers from any source |
| Cabuloan | 479 | 0 | Dead zone: no towers from any source |
| Cacabugaoan | 2,117 | 1 | Crowdsourced signal only (no registered tower) |
| Calanutian | 235 | 0 | Dead zone: no towers from any source |
| Calaocan | 684 | 3 | Crowdsourced signal only (no registered tower) |
| Camangaan | 356 | 0 | Dead zone: no towers from any source |
| Camindoroan | 876 | 0 | Dead zone: no towers from any source |
| Casaratan | 1,884 | 0 | Dead zone: no towers from any source |
| Dalumpinas | 748 | 0 | Dead zone: no towers from any source |
| Fianza | 4,864 | 1 | Crowdsourced signal only (no registered tower) |
| Lungao | 868 | 0 | Dead zone: no towers from any source |
| Malico | 957 | 0 | Dead zone: no towers from any source |
| Malilion | 752 | 0 | Dead zone: no towers from any source |
| Nagkaysa | 961 | 0 | Dead zone: no towers from any source |
| Nining | 1,207 | 0 | Dead zone: no towers from any source |
| Poblacion East | 3,680 | 0 | Dead zone: no towers from any source |
| Poblacion West | 763 | 0 | Dead zone: no towers from any source |
| Salingcob | 349 | 0 | Dead zone: no towers from any source |
| Salpad | 1,514 | 0 | Dead zone: no towers from any source |
| San Felipe East | 2,442 | 0 | Dead zone: no towers from any source |
| San Felipe West | 1,061 | 0 | Dead zone: no towers from any source |
| San Isidro (Sta. Cruzan) | 448 | 0 | Dead zone: no towers from any source |
| San Jose | 564 | 0 | Dead zone: no towers from any source |
| San Rafael Centro | 692 | 0 | Dead zone: no towers from any source |
| San Rafael East | 1,717 | 1 | Crowdsourced signal only (no registered tower) |
| San Rafael West | 2,021 | 0 | Dead zone: no towers from any source |
| San Roque | 1,969 | 1 | Crowdsourced signal only (no registered tower) |
| Santa Maria East | 1,301 | 2 | Crowdsourced signal only (no registered tower) |
| Santa Maria West | 829 | 1 | Crowdsourced signal only (no registered tower) |
| Santo Tomas | 352 | 0 | Dead zone: no towers from any source |
| Siblot | 1,186 | 2 | Crowdsourced signal only (no registered tower) |
| Sobol | 1,644 | 0 | Dead zone: no towers from any source |