San Juan comprises 41 barangays with an estimated population of 40,365. 24 of its barangays (59%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| Allangigan | 494 | 0 | Dead zone: no towers from any source |
| Aludaid | 464 | 1 | Crowdsourced signal only (no registered tower) |
| Bacsayan | 939 | 0 | Dead zone: no towers from any source |
| Balballosa | 531 | 0 | Dead zone: no towers from any source |
| Bambanay | 325 | 1 | Crowdsourced signal only (no registered tower) |
| Bugbugcao | 570 | 0 | Dead zone: no towers from any source |
| Caarusipan | 807 | 0 | Dead zone: no towers from any source |
| Cabaroan | 795 | 0 | Dead zone: no towers from any source |
| Cabugnayan | 894 | 0 | Dead zone: no towers from any source |
| Cacapian | 2,212 | 2 | Crowdsourced signal only (no registered tower) |
| Caculangan | 677 | 0 | Dead zone: no towers from any source |
| Calincamasan | 828 | 0 | Dead zone: no towers from any source |
| Casilagan | 389 | 0 | Dead zone: no towers from any source |
| Catdongan | 412 | 3 | Crowdsourced signal only (no registered tower) |
| Dangdangla | 1,400 | 1 | Crowdsourced signal only (no registered tower) |
| Dasay | 568 | 0 | Dead zone: no towers from any source |
| Dinanum | 933 | 0 | Dead zone: no towers from any source |
| Duplas | 665 | 0 | Dead zone: no towers from any source |
| Guinguinabang | 1,073 | 1 | Crowdsourced signal only (no registered tower) |
| Ili Norte (Pob.) | 2,951 | 9 | Crowdsourced signal only (no registered tower) |
| Ili Sur (Pob.) | 2,078 | 9 | Crowdsourced signal only (no registered tower) |
| Legleg | 743 | 1 | Crowdsourced signal only (no registered tower) |
| Lubing | 491 | 1 | Crowdsourced signal only (no registered tower) |
| Nadsaag | 813 | 1 | Crowdsourced signal only (no registered tower) |
| Nagsabaran | 671 | 0 | Dead zone: no towers from any source |
| Naguirangan | 740 | 0 | Dead zone: no towers from any source |
| Naguituban | 1,271 | 1 | Crowdsourced signal only (no registered tower) |
| Nagyubuyuban | 210 | 0 | Dead zone: no towers from any source |
| Oaquing | 291 | 1 | Crowdsourced signal only (no registered tower) |
| Pacpacac | 538 | 0 | Dead zone: no towers from any source |
| Pagdildilan | 416 | 0 | Dead zone: no towers from any source |
| Panicsican | 1,045 | 5 | Crowdsourced signal only (no registered tower) |
| Quidem | 482 | 0 | Dead zone: no towers from any source |
| San Felipe | 1,576 | 0 | Dead zone: no towers from any source |
| Santa Rosa | 472 | 0 | Dead zone: no towers from any source |
| Santo Rosario | 1,108 | 0 | Dead zone: no towers from any source |
| Saracat | 344 | 0 | Dead zone: no towers from any source |
| Sinapangan | 551 | 0 | Dead zone: no towers from any source |
| Taboc | 2,857 | 13 | Crowdsourced signal only (no registered tower) |
| Talogtog | 2,802 | 1 | Crowdsourced signal only (no registered tower) |
| Urbiztondo | 2,939 | 20 | Crowdsourced signal only (no registered tower) |