The 2016 Seattle Reign FC season was the club's fourth season of play and their fourth season in the National Women's Soccer League, the top division of women's soccer in the United States. The club entered the season as the two-time defending winner of the NWSL Shield.
For transfers in, dates listed are when the Reign FC officially signed the players to the roster. Transactions where only the rights to the players are acquired (e.g., draft picks) are not listed, and amateur call-ups are not considered official signings either. For transfers out, dates listed are when the Reign FC officially removed the players from its roster, not when they signed with another club. If a player later signed with another club, her new club will be noted, but the date listed here remains the one when she was officially removed from the Reign FC roster.
Draft picks are not automatically signed to the team roster. Only those who are signed to a contract will be listed as transfers in. Only trades involving draft picks and executed during the 2016 NWSL College Draft on January 15, 2016, will be listed in the notes.