Sonnett attended the USWNT July training camp and was soon after named to the roster for the 2018 Tournament of Nations.[105][106] Sonnett started all three games at right-back during the Tournament of Nations and registered an assist to Alex Morgan's goal in the 26th minute against Japan.[107][108] Sonnett was also named to the 20-player roster for the 2018 CONCACAF Women's Championship in September.[109][110] She appeared in three of the five match-ups during the tournament, including the game (6–0 win over Jamaica) which ultimately qualified the USWNT for the 2019 FIFA Women's World Cup.[111][112][113] Sonnett closed out 2018 with the USWNT appearing in international friendlies against Portugal and Scotland.[114][115]