San Luis comprises 25 barangays with an estimated population of 38,637. 21 of its barangays (84%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| Anislagan | 478 | 0 | Dead zone: no towers from any source |
| Balit | 929 | 0 | Dead zone: no towers from any source |
| Baylo | 1,861 | 0 | Dead zone: no towers from any source |
| Binicalan | 3,194 | 0 | Dead zone: no towers from any source |
| Cecilia | 1,099 | 0 | Dead zone: no towers from any source |
| Coalicion | 1,319 | 0 | Dead zone: no towers from any source |
| Culi | 961 | 0 | Dead zone: no towers from any source |
| Dimasalang | 1,153 | 0 | Dead zone: no towers from any source |
| Don Alejandro | 2,862 | 0 | Dead zone: no towers from any source |
| Don Pedro | 620 | 0 | Dead zone: no towers from any source |
| Doña Flavia | 1,095 | 0 | Dead zone: no towers from any source |
| Doña Maxima | 933 | 15 | Crowdsourced signal only (no registered tower) |
| Mahagsay | 994 | 0 | Dead zone: no towers from any source |
| Mahapag | 385 | 0 | Dead zone: no towers from any source |
| Mahayahay | 2,867 | 1 | Registered tower only (not crowd-verified) |
| Muritula | 1,916 | 0 | Dead zone: no towers from any source |
| Nuevo Trabajo | 1,953 | 2 | Crowdsourced signal only (no registered tower) |
| Poblacion | 2,670 | 0 | Dead zone: no towers from any source |
| Policarpo | 709 | 0 | Dead zone: no towers from any source |
| San Isidro | 1,910 | 0 | Dead zone: no towers from any source |
| San Pedro | 4,455 | 0 | Dead zone: no towers from any source |
| Santa Ines | 2,989 | 1 | Crowdsourced signal only (no registered tower) |
| Santa Rita | 758 | 0 | Dead zone: no towers from any source |
| Santiago | 215 | 0 | Dead zone: no towers from any source |
| Wegguam | 312 | 0 | Dead zone: no towers from any source |