| Event | Time | Meet | Date |
|---|---|---|---|
| 100m Backstroke | 1:16.19 | MAC Summer Invitational | 2025-07-24 |
| 100m Backstroke | 1:12.16 | MAC Jingle Bell | 2025-12-12 |
| 100m Breaststroke | 1:14.07 | 2026 Ontario Age Groups - MPAC | 2026-03-05 |
| 100m Breaststroke | 1:14.98 | 2026 Central Region Div 1 SC Championships | 2026-02-06 |
| 100m Butterfly | 1:13.67 | Border City Invitational 2025 | 2025-12-05 |
| 100m Freestyle | 1:02.18 | MAC Winter Invitational | 2026-01-22 |
| 100m Freestyle | 59.32 | Border City Invitational 2025 | 2025-12-05 |
| 100m IM | 1:10.19 | MAC Fall Fest Invitational | 2025-10-18 |
| 200m Backstroke | 2:33.82 | MAC Fall Fest Invitational | 2025-10-18 |
| 200m Breaststroke | 2:41.09 | 2026 Ontario Age Groups - MPAC | 2026-03-05 |
| 200m Breaststroke | 2:37.98 | Border City Invitational 2025 | 2025-12-05 |
| 200m Butterfly | 2:47.69 | MAC Jingle Bell | 2025-12-12 |
| 200m Freestyle | 2:16.58 | MAC Summer Invitational | 2025-07-24 |
| 200m Freestyle | 2:10.21 | Gus Ryder Memorial Cup 2025 | 2025-11-07 |
| 200m IM | 2:27.18 | 2026 Ontario Age Groups - MPAC | 2026-03-05 |
| 200m IM | 2:25.16 | Border City Invitational 2025 | 2025-12-05 |
| 400m Freestyle | 4:55.37 | MAC Summer Invitational | 2025-07-24 |
| 400m Freestyle | 4:38.42 | 2025 Summer Divisionals Island & Coastal Vancouver | 2025-06-27 |
| 400m IM | 5:25.10 | MAC Summer Invitational | 2025-07-24 |
| 400m IM | 5:13.82 | MAC Jingle Bell | 2025-12-12 |
| 50m Backstroke | 34.56 | MAC Winter Invitational | 2026-01-22 |
| 50m Backstroke | 33.08 | MAC Jingle Bell | 2025-12-12 |
| 50m Breaststroke | 35.07 | Border City Invitational 2025 | 2025-12-05 |
| 50m Butterfly | 31.72 | MAC Winter Invitational | 2026-01-22 |
| 50m Butterfly | 31.86 | MAC Fall Fest Invitational | 2025-10-18 |
| 50m Freestyle | 28.24 | MAC Winter Invitational | 2026-01-22 |
| 50m Freestyle | 28.39 | MAC Fall Fest Invitational | 2025-10-18 |
| 800m Freestyle | 9:59.67 | MAC Summer Invitational | 2025-07-24 |
| 800m Freestyle | 9:28.91 | Gus Ryder Memorial Cup 2025 | 2025-11-07 |
Sion Lee's top personal bests include 100m Backstroke (1:16.19), 100m Backstroke (1:12.16), 100m Breaststroke (1:14.07), 100m Breaststroke (1:14.98), 100m Butterfly (1:13.67).
Sion Lee swims for Markham Aquatic Club.
Sion Lee has competed in 9 meets.