In February 2016, Rees entered the 2016 EBSA European Under-18 Snooker Championship as the number 15 seed, he managed to advance to the final where he defeated fellow countryman Jackson Page 5–2 in the final to win the inaugural championship. As a result, Rees was awarded a place in the qualifying rounds for the 2016 World Snooker Championship. He lost 10–0 there to Jimmy Robertson. The following season Rees was awarded a wildcard entry in the 2017 Welsh Open. However he was defeated in the first round 4-1 by Jamie Jones. Rees was again awarded with a place in the qualifying rounds for the World Championship, where once again he was defeated at the first hurdle, losing 10–2 to China's Xiao Guodong.