| 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 |
| Teleri | Woman | Welsh Names |
| Telyn | Woman | Welsh Names |
| Terrwyn | Woman | Welsh Names |
| Trefor | Man | Welsh Names |
| Tremain | Man | Welsh Names |
| Trevelian | Man | Welsh Names |
| Tristan | Unisex | Welsh Names |
| Tudor | Man | Welsh Names |
| Twm | Man | Welsh Names |