Harmony made its debut in the Outernatia Song Contest at the 20th edition held in Wyverncliff, Alteus. Their entry was internally selected by the public broadcaster HBS. On March 7, 2016 HBS formally selected Gnash with the song "I Hate U, I Love U" featuring Olivia O'Brien to be Harmony's debut entry to the contest.
Harmony performed fifth in the second semi-final, finishing in eleventh place and gathering 49 points from eight other countries. Harmony therefore did not qualify for the final.