| Cadell | Man | Welsh Names |
| Cadewyn | Unisex | Welsh Names |
| Cadfael | Man | Welsh Names |
| Cadfan | Man | Welsh Names |
| Cadogan | Man | Welsh Names |
| Caerwyn | Unisex | Welsh Names |
| Cai | Unisex | Welsh Names |
| Cambrie | Unisex | Welsh Names |
| Caradoc | Man | Welsh Names |
| Caraf | Woman | Welsh Names |
| Cari | Woman | Welsh Names |
| Cariad | Unisex | Welsh Names |
| Caron | Woman | Welsh Names |
| Carwyn | Man | Welsh Names |
| Carys | Woman | Welsh Names |
| Catrin | Woman | Welsh Names |
| Ceinwen | Woman | Welsh Names |
| Celyn | Unisex | Welsh Names |
| Ceri | Unisex | Welsh Names |
| Ceridwen | Woman | Welsh Names |