| Event | Time | Meet | Date |
|---|---|---|---|
| 100m Backstroke | 1:13.45 | 2025 Alex Baumann Invitational | 2025-11-21 |
| 100m Breaststroke | 1:32.37 | June Performance Meet 2025 | 2025-06-06 |
| 100m Butterfly | 1:15.87 | RHAC Fall Classic 2025 | 2025-10-24 |
| 100m Freestyle | 1:05.41 | June Performance Meet 2025 | 2025-06-06 |
| 100m Freestyle | 1:03.46 | RHAC Fall Classic 2025 | 2025-10-24 |
| 100m IM | 1:14.87 | RHAC Fall Classic 2025 | 2025-10-24 |
| 200m Backstroke | 2:43.55 | RHAC Winter Invitational 2026 | 2026-01-16 |
| 200m Backstroke | 2:30.49 | 2025 MSSAC Open | 2025-12-19 |
| 200m Breaststroke | 3:19.86 | June Performance Meet 2025 | 2025-06-06 |
| 200m Butterfly | 2:56.55 | RHAC Winter Invitational 2026 | 2026-01-16 |
| 200m Butterfly | 2:57.43 | 2025 MSSAC Open | 2025-12-19 |
| 200m Freestyle | 2:14.39 | 2026 Ontario Age Groups - MPAC | 2026-03-05 |
| 200m Freestyle | 2:12.06 | 2026 Central Region Div 1 SC Championships | 2026-02-06 |
| 200m IM | 2:43.70 | RHAC Winter Invitational 2026 | 2026-01-16 |
| 200m IM | 2:31.23 | 2025 Alex Baumann Invitational | 2025-11-21 |
| 400m Freestyle | 4:51.51 | 2026 Ontario Age Groups - MPAC | 2026-03-05 |
| 400m Freestyle | 4:34.94 | 2025 Alex Baumann Invitational | 2025-11-21 |
| 400m IM | 5:48.81 | June Performance Meet 2025 | 2025-06-06 |
| 400m IM | 5:33.33 | RHAC Fall Classic 2025 | 2025-10-24 |
| 50m Backstroke | 35.55 | RHAC Fall Classic 2025 | 2025-10-24 |
| 50m Butterfly | 33.35 | RHAC Winter Invitational 2026 | 2026-01-16 |
| 50m Butterfly | 32.92 | 2025 Alex Baumann Invitational | 2025-11-21 |
| 50m Freestyle | 30.35 | RHAC Winter Invitational 2026 | 2026-01-16 |
| 50m Freestyle | 28.71 | 2026 Central Region Div 1 SC Championships | 2026-02-06 |
| 800m Freestyle | 9:35.59 | 2026 Ontario Age Groups - MPAC | 2026-03-05 |
| 800m Freestyle | 9:26.32 | 2025 Alex Baumann Invitational | 2025-11-21 |
Tkachenko, Gregory's top personal bests include 100m Backstroke (1:13.45), 100m Breaststroke (1:32.37), 100m Butterfly (1:15.87), 100m Freestyle (1:05.41), 100m Freestyle (1:03.46).
Tkachenko, Gregory swims for The Richmond Hill Aquatic Club.
Tkachenko, Gregory has competed in 9 meets.