| Event | Time | Meet | Date |
|---|---|---|---|
| 100m Backstroke | 1:14.48 | Western Region Long Course Championships | 2025-06-13 |
| 100m Backstroke | 1:11.89 | Hall of Fame | 2025-10-18 |
| 100m Breaststroke | 1:29.33 | Hall of Fame | 2025-10-18 |
| 100m Butterfly | 1:18.46 | BAD Outdoor LC Invitational | 2025-06-20 |
| 100m Butterfly | 1:11.83 | 2025 HAC Steeltown Invitational | 2025-11-28 |
| 100m Freestyle | 1:00.14 | 2026 Ontario Age Groups - MPAC | 2026-03-05 |
| 100m Freestyle | 58.63 | Western Region Short Course Championships | 2026-02-12 |
| 200m Backstroke | 2:40.76 | Western Region Long Course Championships | 2025-06-13 |
| 200m Backstroke | 2:32.81 | Gus Ryder Memorial Cup 2025 | 2025-11-07 |
| 200m Breaststroke | 3:33.91 | BAD Outdoor LC Invitational | 2025-06-20 |
| 200m Butterfly | 2:49.68 | 2025 HAC Steeltown Invitational | 2025-11-28 |
| 200m Freestyle | 2:13.53 | 2026 Ontario Age Groups - MPAC | 2026-03-05 |
| 200m Freestyle | 2:09.31 | Gus Ryder Memorial Cup 2025 | 2025-11-07 |
| 200m IM | 2:44.66 | Western Region Long Course Championships | 2025-06-13 |
| 200m IM | 2:30.74 | Gus Ryder Memorial Cup 2025 | 2025-11-07 |
| 400m Freestyle | 4:56.01 | Western Region Long Course Championships | 2025-06-13 |
| 400m Freestyle | 4:44.37 | Western Region Short Course Championships | 2026-02-12 |
| 400m IM | 5:37.10 | 2025 HAC Steeltown Invitational | 2025-11-28 |
| 50m Backstroke | 34.79 | Western Region Long Course Championships | 2025-06-13 |
| 50m Backstroke | 31.53 | Western Region Short Course Championships | 2026-02-12 |
| 50m Breaststroke | 39.47 | Hall of Fame | 2025-10-18 |
| 50m Butterfly | 32.00 | Western Region Long Course Championships | 2025-06-13 |
| 50m Butterfly | 30.76 | 2025 HAC Steeltown Invitational | 2025-11-28 |
| 50m Freestyle | 27.72 | 2026 Ontario Age Groups - MPAC | 2026-03-05 |
| 50m Freestyle | 26.35 | Western Region Short Course Championships | 2026-02-12 |
| 800m Freestyle | 10:09.74 | Western Region Long Course Championships | 2025-06-13 |
| 800m Freestyle | 9:47.32 | Gus Ryder Memorial Cup 2025 | 2025-11-07 |
Johnston, Coen's top personal bests include 100m Backstroke (1:14.48), 100m Backstroke (1:11.89), 100m Breaststroke (1:29.33), 100m Butterfly (1:18.46), 100m Butterfly (1:11.83).
Johnston, Coen swims for Hamilton Aquatic Club.
Johnston, Coen has competed in 10 meets.