| Event | Time | Meet | Date |
|---|---|---|---|
| 100m Breaststroke | 1:17.61 | Western Region Long Course Championships | 2025-06-13 |
| 100m Breaststroke | 1:16.40 | Western Region Short Course Championships | 2026-02-12 |
| 100m Butterfly | 1:10.74 | Western Region Long Course Championships | 2025-06-13 |
| 100m Butterfly | 1:04.32 | Western Region Short Course Championships | 2026-02-12 |
| 100m Freestyle | 57.99 | MAC Winter Invitational | 2026-01-22 |
| 100m Freestyle | 55.75 | Western Region Short Course Championships | 2026-02-12 |
| 100m IM | 1:08.14 | OUA Sprint Invitational - Semis Results | 2025-10-18 |
| 200m Breaststroke | 2:46.98 | Western Region Long Course Championships | 2025-06-13 |
| 200m Breaststroke | 2:38.34 | Western Region Short Course Championships | 2026-02-12 |
| 200m Freestyle | 2:09.97 | Western Region Long Course Championships | 2025-06-13 |
| 200m Freestyle | 2:02.55 | Western Region Short Course Championships | 2026-02-12 |
| 200m IM | 2:28.38 | Western Region Long Course Championships | 2025-06-13 |
| 200m IM | 2:35.30 | Walker Invitational | 2025-10-25 |
| 400m Freestyle | 4:43.59 | Walker Invitational | 2025-10-25 |
| 50m Backstroke | 33.13 | MAC Winter Invitational | 2026-01-22 |
| 50m Breaststroke | 35.35 | Western Region Long Course Championships | 2025-06-13 |
| 50m Breaststroke | 34.26 | LAC - Nothers Fall Invitational | 2025-11-21 |
| 50m Butterfly | 28.65 | MAC Winter Invitational | 2026-01-22 |
| 50m Butterfly | 28.15 | Western Region Short Course Championships | 2026-02-12 |
| 50m Freestyle | 25.85 | Western Region Short Course Championships | 2026-02-12 |
Parsons, William's top personal bests include 100m Breaststroke (1:17.61), 100m Breaststroke (1:16.40), 100m Butterfly (1:10.74), 100m Butterfly (1:04.32), 100m Freestyle (57.99).
Parsons, William swims for Royal City Aquatics.
Parsons, William has competed in 9 meets.