Debut: Yet to make her debut
Current Club: Sydney FC
Previous Clubs: Western Sydney Wanderers
Mathyssen-Whyman was first called up to the Australian under-17 team in 2013 for the 2013 AFC U-16 Women's Championship, aged thirteen at the time. She made her debut for Australia under-20 in a 2–0 win over Uzbekistan in the group stage of the 2015 AFC U-19 Women's Championship, helping Australia to their first win in the 2015 group stage.
Her performance at the youth level and in the domestic league saw her rewarded with her first Senior national team call-up, joining the squad for two friendlies against France and England in October 2018.