| Event | Time | Meet | Date |
|---|---|---|---|
| 100m Backstroke | 1:13.45 | 2025 Alex Baumann Invitational | 2025-11-21 |
| 100m Butterfly | 1:15.87 | RHAC Fall Classic 2025 | 2025-10-24 |
| 100m Freestyle | 1:03.46 | RHAC Fall Classic 2025 | 2025-10-24 |
| 100m IM | 1:14.87 | RHAC Fall Classic 2025 | 2025-10-24 |
| 1500m Freestyle | 1:29.65 | RHAC Distance Duel 2025 | 2025-11-13 |
| 200m Backstroke | 2:30.49 | 2025 MSSAC Open | 2025-12-19 |
| 200m Butterfly | 2:57.43 | 2025 MSSAC Open | 2025-12-19 |
| 200m Freestyle | 2:12.06 | 2026 Central Region Div 1 SC Championships | 2026-02-06 |
| 200m IM | 2:31.23 | 2025 Alex Baumann Invitational | 2025-11-21 |
| 400m Freestyle | 4:34.94 | 2025 Alex Baumann Invitational | 2025-11-21 |
| 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 | 32.92 | 2025 Alex Baumann Invitational | 2025-11-21 |
| 50m Freestyle | 28.71 | 2026 Central Region Div 1 SC Championships | 2026-02-06 |
| 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 Butterfly (1:15.87), 100m Freestyle (1:03.46), 100m IM (1:14.87), 1500m Freestyle (1:29.65).
Tkachenko, Gregory swims for The Richmond Hill Aquatic Club.
Tkachenko, Gregory has competed in 10 meets.