| Event | Time | Meet | Date |
|---|---|---|---|
| 100m Backstroke | 1:17.40 | AAA LCM #3 | 2025-05-23 |
| 100m Backstroke | 1:10.97 | 2026 AA & AAA Winter Champs | 2026-03-05 |
| 100m Breaststroke | 1:30.65 | AAA LCM #3 | 2025-05-23 |
| 100m Breaststroke | 1:19.30 | 2026 AA & AAA Winter Champs | 2026-03-05 |
| 100m Butterfly | 1:24.19 | 2026 AAA #2 LC Invitational | 2026-02-21 |
| 100m Freestyle | 1:06.12 | AAA/AA #5 LCM Invitational Swim Meet | 2026-04-25 |
| 100m Freestyle | 1:04.65 | Age Group Development #3 | 2025-11-22 |
| 100m IM | 1:15.26 | 2025 DAL Sprint Meet | 2025-10-19 |
| 200m Backstroke | 2:44.74 | AAA/AA #5 LCM Invitational Swim Meet | 2026-04-25 |
| 200m Backstroke | 2:36.01 | 2026 AA & AAA Winter Champs | 2026-03-05 |
| 200m Breaststroke | 3:12.76 | AAA LCM #3 | 2025-05-23 |
| 200m Breaststroke | 2:55.10 | 2026 AA & AAA Winter Champs | 2026-03-05 |
| 200m Butterfly | 3:33.01 | AGD Distance Meet North | 2025-11-09 |
| 200m IM | 2:53.72 | AAA LCM #3 | 2025-05-23 |
| 200m IM | 2:51.27 | Age Group Development #3 | 2025-11-22 |
| 400m IM | 5:56.92 | 2025 Candy Cane Invitational | 2025-12-12 |
| 50m Backstroke | 34.19 | AAA/AA #5 LCM Invitational Swim Meet | 2026-04-25 |
| 50m Backstroke | 34.71 | Age Group Development #3 | 2025-11-22 |
| 50m Breaststroke | 37.94 | 2026 AAA #2 LC Invitational | 2026-02-21 |
| 50m Breaststroke | 35.19 | 2026 AA & AAA Winter Champs | 2026-03-05 |
| 50m Butterfly | 33.54 | AAA/AA #5 LCM Invitational Swim Meet | 2026-04-25 |
| 50m Butterfly | 35.10 | 2025 DAL Sprint Meet | 2025-10-19 |
| 50m Freestyle | 28.42 | 2026 AA & AAA Winter Champs | 2026-03-05 |
| 800m Freestyle | 11:14.05 | AGD Distance Meet North | 2025-11-09 |
Harnum, Nicholas's top personal bests include 100m Backstroke (1:17.40), 100m Backstroke (1:10.97), 100m Breaststroke (1:30.65), 100m Breaststroke (1:19.30), 100m Butterfly (1:24.19).
Harnum, Nicholas swims for Sackville Waves Aquatic Team.
Harnum, Nicholas has competed in 9 meets.