| Bleidd | A Welsh name meaning the wolf. |
| Blodwen | A name meaning blessed flower. |
| Blodwyn | A name meaning fair or white flower. |
| Brac | A name meaning a fragment. |
| Bradwen | Legendary son of Moren. |
| Bradwr | A Welsh name meaning a traitor. |
| Braen | A name meaning a hill or high ground. |
| Braith | A name meaning spotted or freckled. |
| Brangwen | A name meaning white raven. |
| Brangwy | A name meaning fair raven. |
| Branwenn | A beautiful blessed raven. |
| Brathach | Legendary son of Gwawrddur. |
| Bregus | A name meaning noble strength. |
| Briallan | A Welsh name meaning primrose flower. |
| Briallen | A Welsh name meaning primrose flower. |
| Bronwen | "White, fair, blessed breast." |
| Bronwyn | Of pale skin or |
| Brychan | Speckled; Spotted |
| Bryn | Hill; Hill. Many Welsh place names begin with the word 'Bryn'. |
| Brynmor | A Welsh name meaning large hill or mound. |
| Brynn | A Welsh name meaning a hill or a mound. |
| Brysen | descendant of Brice |
| Buddug | Welsh form of Victoria: victory. |
| Bushra | Happy news. Glad tiding. Good omen. |
| BwIch | Legendary son of Cleddyv Kyvwkh. |
| Cadarn | Strong, mighty, or powerful. |
| Cadawg | Battle honor or war glory. |
| Caddell | Variant of Cadell: Small battle; spirit of the battle. |
| Caddoc | One who is battletested. |
| Caddock | War-ready; battle sharp. |
| Cadel | Variant of Cadell: Small battle; spirit of the battle. |
| Cadellin | Legendary father of Gweir. |
| Cadwalader | Variant of Cadwaladr: War leader; battle leader. |
| Cadwaladr | Battle leader. This name dates back to the 7th century. More commonly used as a surname than a first name in the present day. |
| Cadwaladyr | Variant of Cadwaladr: War leader; battle leader. |
| Cadwallader | Battle leader. This name dates back to the 7th century. More commonly used as a surname than a first name in the present day. |
| Cadwallen | Battle disolver. Also a variant of Cadwallon: Arranges the battle. |
| Cadwgawn | Legendary son of Iddon. |
| Cadwr | Legendary son of Gwlyon. |
| Cadwy | Legendary son of Gereint. |