| 1. Round | 06/09/2017 | SD Formentera | - | SD Tarazona | 5:4 pso | ||||
| 3. Round | 20/09/2017 | SD Formentera | - | UD Logroñés | 4:3 aet | ||||
| 4. Round | 25/10/2017 | SD Formentera | - | Athletic Club | 1:1 | ||||
| 4. Round | 29/11/2017 | Athletic Club | - | SD Formentera | 0:1 | ||||
| Round of 16 | 03/01/2018 | SD Formentera | - | CD Alavés | 1:3 | ||||
| Round of 16 | 10/01/2018 | CD Alavés | - | SD Formentera | 2:0 |
Spain