Sibulan comprises 15 barangays with an estimated population of 59,730. 3 of its barangays (20%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| Agan-an | 6,624 | 44 | Crowdsourced signal only (no registered tower) |
| Ajong | 4,769 | 6 | Verified coverage (NTC + crowdsourced) |
| Balugo | 1,744 | 0 | Dead zone: no towers from any source |
| Bolocboloc | 5,387 | 18 | Verified coverage (NTC + crowdsourced) |
| Calabnugan | 1,041 | 1 | Crowdsourced signal only (no registered tower) |
| Cangmating | 4,364 | 15 | Verified coverage (NTC + crowdsourced) |
| Enrique Villanueva | 2,135 | 12 | Crowdsourced signal only (no registered tower) |
| Looc | 6,247 | 8 | Verified coverage (NTC + crowdsourced) |
| Magatas | 2,835 | 5 | Verified coverage (NTC + crowdsourced) |
| Maningcao | 799 | 0 | Dead zone: no towers from any source |
| Maslog | 6,283 | 16 | Crowdsourced signal only (no registered tower) |
| Poblacion | 7,189 | 11 | Verified coverage (NTC + crowdsourced) |
| San Antonio | 4,663 | 1 | Crowdsourced signal only (no registered tower) |
| Tubigon | 396 | 0 | Dead zone: no towers from any source |
| Tubtubon | 5,254 | 11 | Verified coverage (NTC + crowdsourced) |