| Event | Time | Meet | Date |
|---|---|---|---|
| 100m Backstroke | 1:41.35 | Winter Classic | 2026-01-16 |
| 100m Backstroke | 1:39.30 | Winter Solstice | 2025-11-29 |
| 100m Breaststroke | 2:02.13 | Winter Solstice | 2025-11-29 |
| 100m Freestyle | 1:35.99 | Winter Classic | 2026-01-16 |
| 100m Freestyle | 1:37.58 | Winter Solstice | 2025-11-29 |
| 100m IM | 1:41.02 | Saskatchewan Racing Series #4 – South Division | 2026-04-25 |
| 200m Backstroke | 3:33.02 | Winter Classic | 2026-01-16 |
| 200m Backstroke | 3:20.16 | Saskatchewan Racing Series #4 – South Division | 2026-04-25 |
| 200m IM | 3:51.98 | Winter Classic | 2026-01-16 |
| 50m Backstroke | 46.18 | Winter Classic | 2026-01-16 |
| 50m Backstroke | 44.65 | 2026 Sask racing Series South Division | 2025-12-06 |
| 50m Breaststroke | 1:00.52 | Winter Classic | 2026-01-16 |
| 50m Breaststroke | 58.00 | Norm Banfield Memorial Open Development Meet | 2025-10-03 |
| 50m Butterfly | 53.53 | Winter Solstice | 2025-11-29 |
| 50m Freestyle | 44.16 | Winter Classic | 2026-01-16 |
| 50m Freestyle | 39.99 | Saskatchewan Racing Series #4 – South Division | 2026-04-25 |
Markous, Jonathan's top personal bests include 100m Backstroke (1:41.35), 100m Backstroke (1:39.30), 100m Breaststroke (2:02.13), 100m Freestyle (1:35.99), 100m Freestyle (1:37.58).
Markous, Jonathan swims for Regina Optimist Dolphins Swim Team.
Markous, Jonathan has competed in 6 meets.