| Bibno. | Participant | Category | Distance |
|---|---|---|---|
| 240 | Lauren Watchorn | (F) Youth | Youth |
| 106 | Lauryn Turnbull | (F) Junior 17-18 | Junior |
| 268 | Lena Vaillier | (F) Youth | Youth |
| 473 | Leo White | (M) TriStar 2 | Tri Star 2 |
| 324 | Leon Wheeler | (M) Youth | Youth |
| 400 | Lewis Anderson | (M) TriStar 3 | Tri Star 3 |
| 153 | Lewys John | (M) Junior 17-18 | Junior |
| 383 | Liam Brown | (M) TriStar 3 | Tri Star 3 |
| 259 | Libby Coleman | (F) Youth | Youth |
| 258 | Lilly Gibbs | (F) Youth | Youth |
| 357 | Lily Jane Evans-Haggerty | (F) TriStar 3 | Tri Star 3 |
| 270 | Lily Mcgarry | (F) Youth | Youth |
| 347 | Lily Scott | (F) TriStar 3 | Tri Star 3 |
| 510 | Lizzie Tench | (F) PTWC2 | Paratriathlon |
| 341 | Lizzy Edge | (F) TriStar 3 | Tri Star 3 |
| 428 | Lorna Dumbleton | (F) TriStar 2 | Tri Star 2 |
| 291 | Louis Johnston | (M) Youth | Youth |
| 211 | Louis Vitiello | (M) Junior 19 | Junior |
| 194 | Luc Bartlett | (M) Junior 17-18 | Junior |
| 390 | Luca Treadwell | (M) TriStar 3 | Tri Star 3 |
| 454 | Lucy Donnelly | (F) TriStar 2 | Tri Star 2 |
| 442 | Lucy Phillips | (F) TriStar 2 | Tri Star 2 |
| 467 | Luke Holmes | (M) TriStar 2 | Tri Star 2 |
| 478 | Luke Rawcliffe | (M) TriStar 2 | Tri Star 2 |
| 307 | Luke Van Oudtshoorn | (M) Youth | Youth |
| 184 | Luke Williams | (M) Junior 17-18 | Junior |
| 389 | Mack Downey | (M) TriStar 3 | Tri Star 3 |
| 136 | Maddison Drury | (F) Junior 17-18 | Junior |
| 129 | Madeleine Henderson | (F) Junior 19 | Junior |
| 360 | Madeline Grace Cooper | (F) TriStar 3 | Tri Star 3 |
| 429 | Maisie Jensen | (F) TriStar 2 | Tri Star 2 |
| 245 | Mali Jones | (F) Youth | Youth |
| 303 | Marcus Dey | (M) Youth | Youth |
| 502 | Mark Dominic Conway | (M) PTWC2 | Paratriathlon |
| 375 | Martha Calton-Seal | (F) TriStar 3 | Tri Star 3 |
| 322 | Matthew Howard | (M) Youth | Youth |
| 405 | Matthew Howson | (M) TriStar 3 | Tri Star 3 |
| 176 | Matthew Willis | (M) Junior 17-18 | Junior |
| 297 | Matyas Sinko | (M) Youth | Youth |
| 205 | Maurice Calton-Seal | (M) Junior 17-18 | Junior |
| 487 | Max Cooper | (M) TriStar 2 | Tri Star 2 |
| 235 | Megan Finn | (F) Youth | Youth |
| 441 | Melissa Eve Cooper | (F) TriStar 2 | Tri Star 2 |
| 437 | Melissa Turnbull | (F) TriStar 2 | Tri Star 2 |
| 271 | Mia France | (F) Youth | Youth |
| 158 | Michael Eagling | (M) Junior 17-18 | Junior |
| 521 | Michael Taylor | (M) PTS4 | Paratriathlon |
| 434 | Millie Bell | (F) TriStar 2 | Tri Star 2 |
| 253 | Millie Yates | (F) Youth | Youth |
| 257 | Molly Shermer | (F) Youth | Youth |
