It was the fourth season since the club was renamed from Seattle Sounders FC 2 and relocated to Tacoma, Washington.

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

Source: USL Championship, Soccerway Win Draw Loss Upcoming fixture Due to their ownership by a higher division professional club (Seattle Sounders FC), Tacoma is one of 15 teams expressly forbidden from entering the Cup competition.

For transfers in, dates listed are when Tacoma Defiance officially signed the players to the roster.

For transfers out, dates listed are when Defiance officially removed the players from its roster, not when they signed with another club.