| # | Name | Origin | Meaning | Gender | |
|---|---|---|---|---|---|
| 541 | Pany | Welsh | Son of Harry. | M | |
| 542 | Parry | Welsh | Son of Harry. | M | |
| 543 | Pedr | Welsh | Welsh form of Peter 'rock'. | M | |
| 544 | Peissawg | Welsh | Legendary king of Brittany. | M | |
| 545 | Pembroke | Welsh | Lives in the headland. | M | |
| 546 | PenIlyn | Welsh | From the lake's headland. | M | |
| 547 | Penn | Welsh | From the peak. | M | |
| 548 | Penvro | Welsh | From pembroke. | M | |
| 549 | Peredur | Welsh | Legendary son of Evrawg. | M | |
| 550 | Perry | Welsh | Son of Harry. | M | |
| 551 | Plys | Welsh | Son of Rhys. | M | |
| 552 | Powell | Welsh | Son of Howell. | M | |
| 553 | Preece | Welsh | Son of Rhys. | M | |
| 554 | Price | Welsh | Son of Rhys. | M | |
| 555 | Pryderi | Welsh | Legendary son of Pwyll. | M | |
| 556 | Prydwen | Welsh | Handsome. | M | |
| 557 | Puw | Welsh | Welsh form of Pugh 'son of Hugh'. | M | |
| 558 | Pwyll | Welsh | Son of Howell. | M | |
| 559 | Pyrs | Welsh | Welsh form of Pierce 'rock'. | M | |
| 560 | Reece | Welsh | Ardent; fiery. | M | |