| Nominativ | circaea | circaeae |
| Genitiv | circaeae, circaeai | circaearum, circaeum, circaeumque |
| Dativ | circaeai, circaeae | circaeis, circaeabus, circeis |
| Akkusativ | circaeam | circaeas, circeas |
| Ablativ | circaea, circaead | circaeis, circaeabus, circeis |
| Vokativ | circaea | circaeae |
