| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 221 | CIywd | Welsh | Loud voiced. | M | |
| 222 | Cledwyn | Welsh | Rough; blessed. | M | |
| 223 | Clud | Welsh | Lame. | M | |
| 224 | Clust | Welsh | Legendary son of Clustveinydd. | M | |
| 225 | Cnychwr | Welsh | Legendary son of Nes. | M | |
| 226 | Coch | Welsh | Legendary son of Caw. | M | |
| 227 | Coed | Welsh | Dwells in the woods. | M | |
| 228 | Colwin | Welsh | Variant of Colwyn: Name of a river in Wales. | M | |
| 229 | Colwyn | Welsh | Name of a river in Wales. | M | |
| 230 | Colywnn | Welsh | Variant of Colwyn: Name of a river in Wales. | M | |
| 231 | Conway | Welsh | Holy river. Place-name and surname. | M | |
| 232 | Conwy | Welsh | Variant of Conway: Holy river. Place-name and surname. | M | |
| 233 | Conyn | Welsh | Legendary son of Caw 'wise'. | M | |
| 234 | Cordelia | Welsh | Jewel of the sea. | F | |
| 235 | Corsen | Welsh | Reed. | F | |
| 236 | Craddock | Welsh | Affection; beloved. | M | |
| 237 | Cradoe | Welsh | Beloved. | M | |
| 238 | Cragen | Welsh | Shell. | F | |
| 239 | Craig | Welsh | Rock. | M | |
| 240 | Creiddylad | Welsh | Jewel of the sea. | F | |