Sound FC: every transfer in and out, fees paid and earned, squad market value.
| Date | Player | From | To | Fee |
|---|---|---|---|---|
| 2019-05-01 | Josh Bauer | UNH Wildcats | Sounders U23 | Loan |
| 2017-05-01 | Conner Antley | Mercer Bears | Sounders U23 | Loan |
| 2015-05-01 | Brandt Bronico | Charlotte 49ers | Sounders U23 | Loan |
| 2014-05-01 | Jordan Morris | Stanford Card. | Sounders U23 | Loan |
| 2013-05-01 | Earl Edwards Jr. | UCLA Bruins | Sounders U23 | Loan |
| 2012-05-01 | DeAndre Yedlin | Akron Zips | Sounders U23 | Loan |