In 2016, she started the competition season in Hungary at International Tournament Gracia Fair Cup, where she won gold All-around medal in junior category. At the International Tournament Alina Cup in Moscow, she won gold in clubs and rope, bronze in hoop and silver in Team competition. She also competed at International Tournament Baltic Hoop in Riga, Latvia, winning silver medal in Junior All-around. At the 2016 European Junior Championships in Holon, Harnasko won 2 silver medals in team (together with Yulia Isachanka, Julia Evchik) and individual hoop final (tied with Israel's Nicol Zelikman). On September 9–11, Harnasko together with senior teammates Katsiaryna Halkina and Hanna Bazhko represented team Dinamo at the annual 2016 Aeon Cup in Tokyo, where they won the team silver and with Harnasko taking silver in the junior all-around.