| Event | Time | Meet | Date |
|---|---|---|---|
| 100m Backstroke | 1:28.57 | RHAC Winter Invitational 2026 | 2026-01-16 |
| 100m Backstroke | 1:27.72 | 2026 Steve Kingston Memorial | 2026-03-06 |
| 100m Breaststroke | 1:33.10 | RHAC Winter Invitational 2026 | 2026-01-16 |
| 100m Breaststroke | 1:31.62 | 2026 Central Region Div 1 SC Championships | 2026-02-06 |
| 100m Butterfly | 1:43.80 | RHAC Fall Classic 2025 | 2025-10-24 |
| 100m Freestyle | 1:20.85 | RHAC Fall Classic 2025 | 2025-10-24 |
| 200m Backstroke | 3:08.16 | RHAC Winter Invitational 2026 | 2026-01-16 |
| 200m Backstroke | 3:06.26 | 2026 Steve Kingston Memorial | 2026-03-06 |
| 200m Breaststroke | 3:18.60 | RHAC Winter Invitational 2026 | 2026-01-16 |
| 200m Breaststroke | 3:16.59 | 2026 Steve Kingston Memorial | 2026-03-06 |
| 200m Freestyle | 2:54.23 | RHAC Fall Classic 2025 | 2025-10-24 |
| 200m IM | 3:01.72 | 2026 Steve Kingston Memorial | 2026-03-06 |
| 400m Freestyle | 6:01.49 | RHAC Winter Invitational 2026 | 2026-01-16 |
| 400m Freestyle | 6:04.85 | 2025 Fall Distance Time Trial | 2025-11-15 |
| 50m Backstroke | 40.53 | RHAC Winter Invitational 2026 | 2026-01-16 |
| 50m Backstroke | 40.97 | 2026 Steve Kingston Memorial | 2026-03-06 |
| 50m Breaststroke | 43.31 | RHAC Winter Invitational 2026 | 2026-01-16 |
| 50m Breaststroke | 41.39 | 2026 Central Region Div 1 SC Championships | 2026-02-06 |
| 50m Butterfly | 46.51 | RHAC Fall Classic 2025 | 2025-10-24 |
| 50m Freestyle | 36.52 | RHAC Fall Classic 2025 | 2025-10-24 |
| 800m Freestyle | 12:25.94 | RHAC Winter Invitational 2026 | 2026-01-16 |
| 800m Freestyle | 12:24.87 | 2025 Fall Distance Time Trial | 2025-11-15 |
Kolesnik, Lachlan's top personal bests include 100m Backstroke (1:28.57), 100m Backstroke (1:27.72), 100m Breaststroke (1:33.10), 100m Breaststroke (1:31.62), 100m Butterfly (1:43.80).
Kolesnik, Lachlan swims for Newmarket Stingrays Swim Club.
Kolesnik, Lachlan has competed in 8 meets.