The canton Saint-Porchaire has 20 communes.
| Code | Name | Population ▼ |
|---|---|---|
| 17336 | Saint-Georges-des-Coteaux | 2 843 |
| 17387 | Saint-Porchaire | 2 040 |
| 17284 | Pont-l'Abbé-d'Arnoult | 1 811 |
| 17453 | Trizay | 1 538 |
| 17330 | Sainte-Gemme | 1 365 |
| 17285 | Port-d'Envaux | 1 188 |
| 17262 | Nieul-lès-Saintes | 1 186 |
| 17045 | Beurlay | 994 |
| 17408 | Saint-Sulpice-d'Arnoult | 924 |
| 17280 | Plassay | 823 |
| 17255 | Nancras | 794 |
| 17171 | Geay | 788 |
| 17431 | Soulignonne | 752 |
| 17154 | Les Essards | 740 |
| 17455 | La Vallée | 707 |
| 17030 | Balanzac | 642 |
| 17302 | Romegoux | 640 |
| 17389 | Sainte-Radegonde | 589 |
| 17134 | Crazannes | 442 |
| 17148 | Écurat | 438 |