Having been named in the training squad for the 2017 Six Nations Under 20 Championship in December 2016, Wycherley made his debut for Ireland U20 on 3 February 2017 when he started against Scotland U20 in his sides 19–20 away victory in Broadwood Stadium. On 10 February 2017, Wycherley again started for Ireland U20, this time in the sides 26–27 away victory against Italy U20 in Stadio Enrico Chersoni. On 17 March 2017, Wycherley started for Ireland U20 in their 10–14 defeat against England U20 in Donnybrook Stadium. Wycherley was also selected in the Ireland Under-20s squad for the 2017 World Rugby Under 20 Championship.