San Isidro comprises 16 barangays with an estimated population of 30,489. 12 of its barangays (75%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| Baon | 1,925 | 0 | Dead zone: no towers from any source |
| Batobato (Pob.) | 8,513 | 0 | Dead zone: no towers from any source |
| Bitaogan | 1,346 | 0 | Dead zone: no towers from any source |
| Cambaleon | 995 | 0 | Dead zone: no towers from any source |
| Dugmanon | 534 | 2 | Crowdsourced signal only (no registered tower) |
| Iba | 424 | 4 | Crowdsourced signal only (no registered tower) |
| La Union | 5,171 | 0 | Dead zone: no towers from any source |
| Lapu-lapu | 1,403 | 0 | Dead zone: no towers from any source |
| Maag | 1,018 | 0 | Dead zone: no towers from any source |
| Manikling | 2,716 | 3 | Crowdsourced signal only (no registered tower) |
| Maputi | 384 | 0 | Dead zone: no towers from any source |
| San Miguel | 603 | 0 | Dead zone: no towers from any source |
| San Roque | 2,101 | 5 | Crowdsourced signal only (no registered tower) |
| Santo Rosario | 534 | 0 | Dead zone: no towers from any source |
| Sudlon | 701 | 0 | Dead zone: no towers from any source |
| Talisay | 2,121 | 0 | Dead zone: no towers from any source |