Sepp Koster has 4 recorded races from Willemstad, CW.
| Date | Race | Distance | Time | Overall |
|---|---|---|---|---|
| 2026-03-01 | 2026 Life Time 305 Half Marathon & 5K Pres by Baptist Health | Half Marathon | 1:55:53 | 649 |
| 2024-03-03 | 2024 Baptist Health 305 Half Marathon & 5K | Half Marathon | 1:51:48 | 298 |
| 2023-03-05 | 2023 Baptist Health 305 Half Marathon & 5K | Half Marathon | 1:54:46 | 393 |
| 2023-01-28 | Life Time Miami Marathon & Half Half Marathon | Half Marathon | 1:51:47 | 1548 |