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