Joanna Diffey has 6 recorded races.
| Date | Race | Distance | Time | Overall |
|---|---|---|---|---|
| TCS London Marathon 2026 | Marathon | 3:51:15 | 16769 | |
| TCS London Marathon 2025 | Marathon | 3:41:15 | 11761 | |
| BMW Berlin Marathon 2024 | Marathon | 3:47:10 | 3979 | |
| TCS London Marathon 2023 | Marathon | 3:58:02 | 17431 | |
| TCS London Marathon 2022 | Marathon | 4:25:13 | 18932 | |
| BMW Berlin Marathon 2022 | Marathon | 3:40:00 | 1658 |