| 1. Round | 29/03/2018 | Seattle Sounders 2 | - | Fresno FC | 0:1 | ||||
| 2. Round | 12/04/2018 | Seattle Sounders 2 | - | Real Monarchs SLC | 1:3 | ||||
| 3. Round | 06/05/2018 | Seattle Sounders 2 | - | Sacramento Republic | 1:2 | ||||
| 4. Round | 03/06/2018 | Fresno FC | - | Seattle Sounders 2 | 4:0 | ||||
| 6. Round | 12/08/2018 | Seattle Sounders 2 | - | San Antonio FC | 3:2 | ||||
| 6. Round | 30/08/2018 | Seattle Sounders 2 | - | Saint Louis FC | 1:1 | ||||
| 7. Round | 02/09/2018 | Seattle Sounders 2 | - | Orange County SC | 1:1 | ||||
| 8. Round | 04/10/2018 | Seattle Sounders 2 | - | Los Angeles Galaxy II | 2:2 | ||||
| 8. Round | 11/10/2018 | Seattle Sounders 2 | - | Colorado Springs Switchbacks | 2:2 |
USA