| Event | Time | Meet | Date |
|---|---|---|---|
| 100m Breaststroke | 1:37.70 | Winter Waves Invitational | 2026-03-13 |
| 100m Butterfly | 1:39.41 | Bluefins Fall Pentathlon | 2025-11-14 |
| 100m Freestyle | 1:14.69 | Winter Waves Invitational | 2026-03-13 |
| 200m Breaststroke | 3:23.19 | Winter Waves Invitational | 2026-03-13 |
| 200m Freestyle | 2:40.79 | Winter Waves Invitational | 2026-03-13 |
| 200m IM | 3:08.41 | Bluefins Fall Pentathlon | 2025-11-14 |
| 400m Freestyle | 5:32.34 | Winter Waves Invitational | 2026-03-13 |
| 50m Backstroke | 43.50 | Bluefins Fall Pentathlon | 2025-11-14 |
| 50m Breaststroke | 43.34 | Winter Waves Invitational | 2026-03-13 |
Johnston, James's top personal bests include 100m Breaststroke (1:37.70), 100m Butterfly (1:39.41), 100m Freestyle (1:14.69), 200m Breaststroke (3:23.19), 200m Freestyle (2:40.79).
Johnston, James swims for St. John's Legends Swim Club.
Johnston, James has competed in 4 meets.