San Juan comprises 19 barangays with an estimated population of 14,210. 18 of its barangays (95%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| Abualan | 1,486 | 0 | Dead zone: no towers from any source |
| Ba-ug | 1,589 | 0 | Dead zone: no towers from any source |
| Badas | 721 | 0 | Dead zone: no towers from any source |
| Cabcaborao | 957 | 0 | Dead zone: no towers from any source |
| Colabaoan | 195 | 0 | Dead zone: no towers from any source |
| Culiong | 206 | 0 | Dead zone: no towers from any source |
| Daoidao | 219 | 0 | Dead zone: no towers from any source |
| Guimba | 223 | 0 | Dead zone: no towers from any source |
| Lam-ag | 512 | 0 | Dead zone: no towers from any source |
| Lumobang | 360 | 0 | Dead zone: no towers from any source |
| Nangobongan | 317 | 0 | Dead zone: no towers from any source |
| Pattaoig | 154 | 0 | Dead zone: no towers from any source |
| Poblacion North | 1,991 | 1 | Crowdsourced signal only (no registered tower) |
| Poblacion South | 256 | 0 | Dead zone: no towers from any source |
| Quidaoen | 1,439 | 0 | Dead zone: no towers from any source |
| Sabangan | 166 | 0 | Dead zone: no towers from any source |
| Silet | 689 | 0 | Dead zone: no towers from any source |
| Supi-il | 1,196 | 0 | Dead zone: no towers from any source |
| Tagaytay | 1,534 | 0 | Dead zone: no towers from any source |