| Event | Time | Meet | Date |
|---|---|---|---|
| 100m Backstroke | 1:46.33 | MAC Winter Invitational | 2026-01-22 |
| 100m Backstroke | 1:32.56 | 2026 Steve Kingston Memorial | 2026-03-06 |
| 100m Breaststroke | 1:50.03 | 2026 Central Region Div 2 SC Championships | 2026-02-20 |
| 100m Freestyle | 1:31.10 | BAD Outdoor LC Invitational | 2025-06-20 |
| 100m Freestyle | 1:17.68 | 2026 Steve Kingston Memorial | 2026-03-06 |
| 100m IM | 1:34.47 | COBRA 2026 Stephen Clarke Classic | 2026-01-10 |
| 200m Backstroke | 3:16.16 | 2026 Steve Kingston Memorial | 2026-03-06 |
| 200m Freestyle | 3:10.50 | MAC Winter Invitational | 2026-01-22 |
| 200m Freestyle | 2:53.11 | 2026 Steve Kingston Memorial | 2026-03-06 |
| 200m IM | 3:43.25 | MAC Winter Invitational | 2026-01-22 |
| 200m IM | 3:47.56 | 2025 Murray Drudge Invitational | 2025-12-05 |
| 50m Backstroke | 43.92 | MAC Winter Invitational | 2026-01-22 |
| 50m Backstroke | 44.67 | 2025 Murray Drudge Invitational | 2025-12-05 |
| 50m Breaststroke | 53.63 | 2025 Central Region Div 1 LC Championships | 2025-06-20 |
| 50m Breaststroke | 53.18 | 2026 Central Region Div 2 SC Championships | 2026-02-20 |
| 50m Butterfly | 55.06 | 2025 Alex Baumann Invitational | 2025-11-21 |
| 50m Freestyle | 36.72 | MAC Winter Invitational | 2026-01-22 |
| 50m Freestyle | 33.91 | 2026 Steve Kingston Memorial | 2026-03-06 |
Alexander, Sebastian's top personal bests include 100m Backstroke (1:46.33), 100m Backstroke (1:32.56), 100m Breaststroke (1:50.03), 100m Freestyle (1:31.10), 100m Freestyle (1:17.68).
Alexander, Sebastian swims for COBRA Swim Club.
Alexander, Sebastian has competed in 11 meets.