San Julian comprises 16 barangays with an estimated population of 13,213. 14 of its barangays (88%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| Barangay No. 1 Poblacion | 367 | 0 | Dead zone: no towers from any source |
| Barangay No. 2 Poblacion | 94 | 0 | Dead zone: no towers from any source |
| Barangay No. 3 Poblacion | 149 | 0 | Dead zone: no towers from any source |
| Barangay No. 4 Poblacion | 85 | 0 | Dead zone: no towers from any source |
| Barangay No. 5 Poblacion | 15 | 0 | Dead zone: no towers from any source |
| Barangay No. 6 Poblacion | 1,143 | 0 | Dead zone: no towers from any source |
| Bunacan | 544 | 0 | Dead zone: no towers from any source |
| Campidhan | 854 | 0 | Dead zone: no towers from any source |
| Casoroy | 696 | 0 | Dead zone: no towers from any source |
| Libas | 1,512 | 3 | Crowdsourced signal only (no registered tower) |
| Lunang | 326 | 0 | Dead zone: no towers from any source |
| Nena (Luna) | 2,863 | 0 | Dead zone: no towers from any source |
| Pagbabangnan | 1,212 | 1 | Crowdsourced signal only (no registered tower) |
| Putong | 1,565 | 0 | Dead zone: no towers from any source |
| San Isidro | 1,324 | 0 | Dead zone: no towers from any source |
| San Miguel | 464 | 0 | Dead zone: no towers from any source |