San Juan comprises 15 barangays with an estimated population of 11,522. 6 of its barangays (40%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| Canasagan | 488 | 1 | Crowdsourced signal only (no registered tower) |
| Candura | 594 | 0 | Dead zone: no towers from any source |
| Cangmunag | 1,069 | 0 | Dead zone: no towers from any source |
| Cansayang | 483 | 0 | Dead zone: no towers from any source |
| Catulayan | 1,811 | 0 | Dead zone: no towers from any source |
| Lala-o | 579 | 2 | Crowdsourced signal only (no registered tower) |
| Maite | 571 | 8 | Crowdsourced signal only (no registered tower) |
| Napo | 1,062 | 7 | Crowdsourced signal only (no registered tower) |
| Paliton | 448 | 4 | Crowdsourced signal only (no registered tower) |
| Poblacion | 559 | 2 | Verified coverage (NTC + crowdsourced) |
| Solangon | 1,059 | 2 | Crowdsourced signal only (no registered tower) |
| Tag-ibo | 332 | 0 | Dead zone: no towers from any source |
| Tambisan | 816 | 2 | Crowdsourced signal only (no registered tower) |
| Timbaon | 890 | 0 | Dead zone: no towers from any source |
| Tubod | 761 | 4 | Crowdsourced signal only (no registered tower) |