Duncan Harris has 4 recorded races.
| Date | Race | Distance | Time | Overall |
|---|---|---|---|---|
| TCS London Marathon 2025 | Marathon | 4:01:27 | 18322 | |
| TCS London Marathon 2024 | Marathon | 3:41:14 | 13595 | |
| TCS London Marathon 2023 | Marathon | 3:43:57 | 12541 | |
| TCS London Marathon 2022 | Marathon | 3:49:14 | 9773 |