Valjas was born on 2 June 1987 to parents who both played varsity volleyball in university. Growing up, she competed in mountain biking and cross-country skiing. She is the older sister of skier Len Väljas. Like her parents, she played university volleyball for the Toronto Varsity Blues, before transitioning to beach volleyball, where in 2010 she became part of the national team. Valjas formed a double with Jamie Broder in 2011, and went on to win NORCECA continental titles in 2013 and 2015.
