| Event | Time | Meet | Date |
|---|---|---|---|
| 100m Backstroke | 1:35.37 | 2025 Central Region Div 2 LC Championships | 2025-06-13 |
| 100m Backstroke | 1:23.45 | 2026 Steve Kingston Memorial | 2026-03-06 |
| 100m Breaststroke | 1:50.75 | MAC Rising Star #2 | 2025-05-30 |
| 100m Breaststroke | 1:41.04 | 2026 Steve Kingston Memorial | 2026-03-06 |
| 100m Butterfly | 1:30.82 | 2026 Steve Kingston Memorial | 2026-03-06 |
| 100m Freestyle | 1:21.06 | 2025 Central Region Div 2 LC Championships | 2025-06-13 |
| 100m Freestyle | 1:11.81 | 2026 Steve Kingston Memorial | 2026-03-06 |
| 100m IM | 1:33.87 | 2025 Downtown Sprint Meet | 2025-10-25 |
| 200m Backstroke | 3:11.45 | MAC Rising Star #2 | 2025-05-30 |
| 200m Backstroke | 2:56.64 | 2026 MSSAC 14U Future Stars | 2026-01-31 |
| 200m Breaststroke | 3:33.36 | 2026 Central Region Div 2 SC Championships | 2026-02-20 |
| 200m Freestyle | 2:54.20 | 2025 Central Region Div 2 LC Championships | 2025-06-13 |
| 200m Freestyle | 2:35.43 | 2026 Steve Kingston Memorial | 2026-03-06 |
| 200m IM | 3:04.14 | 2026 Central Region Div 2 SC Championships | 2026-02-20 |
| 400m Freestyle | 5:38.57 | 2026 Central Region Div 2 SC Championships | 2026-02-20 |
| 50m Backstroke | 39.00 | 2026 Central Region Div 2 SC Championships | 2026-02-20 |
| 50m Breaststroke | 49.09 | MAC Jingle Bell | 2025-12-12 |
| 50m Butterfly | 39.33 | 2026 Steve Kingston Memorial | 2026-03-06 |
| 50m Freestyle | 34.92 | MAC Rising Star #2 | 2025-05-30 |
| 50m Freestyle | 33.35 | 2026 MSSAC 14U Future Stars | 2026-01-31 |
Williams, Niya's top personal bests include 100m Backstroke (1:35.37), 100m Backstroke (1:23.45), 100m Breaststroke (1:50.75), 100m Breaststroke (1:41.04), 100m Butterfly (1:30.82).
Williams, Niya swims for Toronto Swim Club.
Williams, Niya has competed in 9 meets.