On April 12, 2015 Poland men's national under-19 volleyball team, including Kozub, won title of U19 European Champion 2015. They beat Italy U19 in the final (3–1).[1][2] He took part in European Youth Olympic Festival with Polish national U19 team. On August 1, 2015 he achieved gold medal (final match with Bulgaria 3–0). On August 23, 2015 Poland achieved first title of U19 World Champion. In the final his team beat hosts - Argentina (3–2).[3] On September 10, 2016 he achieved title of the 2016 CEV U20 European Champion after winning 7 of 7 matches in tournament and beating Ukraine U21 in the final (3–1).[4] On July 2, 2017 Poland U21, including Kozub, achieved title of U21 World Champion 2017 after beating Cuba U21 in the final (3–0).[5] Kozub was awarded an individual award for the Best Setter of the whole tournament.[6][7] His national team won 47 matches in the row and never lost.[8] The U21 World Champion title ended up his time in youth national teams.
Polish
