| Locality | Postal Code |
|---|---|
| Albardón, San Cosme | W3412 XAH |
| Arroyo Pelón, San Cosme | W3401 XAP |
| Arroyo San Juan, San Cosme | W3409 XAC |
| Buena Vista, San Cosme | W3412 XAI |
| Colonia Alvarez, San Cosme | W3401 XAQ |
| Colonia M Aberastury, San Cosme | W3409 XAD |
| Colonia Maria Esther, San Cosme | W3401 XAR |
| Colonia Matilde, San Cosme | W3401 XAS |
| Costa, San Cosme | W3401 XAZ |
| Costa Rio Parana, San Cosme | W3401 XBA |
| Costa Toledo, San Cosme | W3409 XAE |
| Desaguadero, San Cosme | W3403 XAA |
| El Pelon, San Cosme | W3401 XAY |
| Ensenada Grande, San Cosme | W3412 XAP |
| Ensenadita, San Cosme | W3412 XAQ |
| Ingenio Primer Correntino, San Cosme | W3401 XAT |
| Isla Ibatay, San Cosme | W3401 XAU |
| Juan Ramon Vidal, San Cosme | W3401 XAV |
| Mandinga, San Cosme | W3412 XAJ |
| Matilde, San Cosme | W3412 XAK |
| Paso de la Patria, San Cosme | W3409 |
| Puerto Araza, San Cosme | W3409 XAB |
| Puerto González, San Cosme | W3409 XAA |
| Rincón, San Cosme | W3409 XAF |
| San Cosme, San Cosme | W3412 |
| San José, San Cosme | W3401 XAW |