Guillermo Gastañeta has 5 recorded races from Perú.
| Date | Race | Distance | Time | Overall |
|---|---|---|---|---|
| 2025-08-24 | 116° KIA MEDIA MARATÓN DE LIMA & 10K BY PUMA 21.097K | Half Marathon | 1:49:27 | 1881 |
| 2025-02-02 | Life Time Miami Marathon & Half presented by FP Movement Half Marathon | Half Marathon | 1:53:16 | 1852 |
| 2024-08-25 | 115° KIA MEDIA MARATÓN DE LIMA & 10K POWERED BY PUMA 21.097K | Half Marathon | 2:02:31 | 3420 |
| 2023-08-27 | KIA MEDIA MARATON DE LIMA Y 10K POWERED BY PUMA 2023 21.097K | Half Marathon | 2:00:09 | 2275 |
| BMW Berlin Marathon 2025 | Marathon | 3:53:35 | 11718 |