The 2017 Seattle Sounders FC 2 season was the club's third year of existence, and their third season in the United Soccer League, the second tier of the United States Soccer Pyramid.

Including previous Seattle Sounders franchises, it was the 37th 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.

[1] Source: USL Win Draw Loss Upcoming fixture Numbers after plus-sign(+) denote appearances as a substitute.