The 2015 Seattle Sounders FC 2 season was the club's first year of existence, and their first season in the United Soccer League, the third tier of the United States soccer pyramid.

Including previous Seattle Sounders franchises, it was the 35th season of a soccer team playing in the Seattle metro area.

Note: Flags indicate national team as defined under FIFA eligibility rules.

Players may hold more than one non-FIFA nationality.

Squad correct as of May 27, 2015.