At the 2010 IIHF World U20 Championships, Conz led the Swiss team to impressive fourth place finish. He managed an upset of the Slovaks by stopping 39 shots in a 4–1 victory. This victory advanced Switzerland to the knockout round to face the highly favoured Russian squad. Against the Russian, Conz had another impressive match where he made 50 saves on 52 shots, as the Swiss advanced 3–2. After losing to the Canadians 6–1 and Swedes 11–4 and out of the medals, Conz finished the tournament with a 4.76 GAA and an 89.31% save percentage, an impressive feat due to the workload the over-matched Swiss defence allowed on Conz. He faced more than 300 shots on goal, making him the tournament's busiest goalie, and his 284 saves in seven games were tournament best. Despite allowing the second most goals in the tournament at 34, he was selected to the tournament all-star team and named the best goaltender.