| Rhoswen | Woman | Welsh Names |
| Rhun | Man | Welsh Names |
| Rhydian | Man | Welsh Names |
| Rhys | Man | Welsh Names |
| Rice | Unisex | Welsh Names |
| Romney | Man | Welsh Names |
| Seren | Woman | Welsh Names |
| Siân | Woman | Welsh Names |
| Siani | Unisex | Welsh Names |
| Siarl | Man | Welsh Names |
| Sioned | Woman | Welsh Names |
| Siriol | Woman | Welsh Names |
| Sulwyn | Woman | Welsh Names |
| Taffy | Man | Welsh Names |
| Talaith | Woman | Welsh Names |
| Talan | Man | Welsh Names |
| Taliesin | Man | Welsh Names |
| Tanwen | Woman | Welsh Names |
| Taran | Man | Welsh Names |
| Tegan | Woman | Welsh Names |