| Saint-Joachim | |
| Commune Status: | Commune |
| Arrondissement: | Saint-Nazaire |
| Canton: | Guérande |
| Insee: | 44168 |
| Postal Code: | 44720 |
| Mayor: | Raphaël Salaün[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | CA Région Nazairienne et Estuaire |
| Coordinates: | 47.3831°N -2.1994°W |
| Elevation M: | 6 |
| Elevation Min M: | 0 |
| Elevation Max M: | 9 |
| Area Km2: | 86.22 |
Saint-Joachim (in French pronounced as /sɛ̃ ʒɔaʃɛ̃/; Breton: Sant-Yoasin) is a commune in the Loire-Atlantique department in western France.[2] It is in the centre of the Brière marsh, and comprises a group of "islands" within the marsh.