2009-10: Austin Lotz played for the Southwest Jets bantam AA team in Manitoba and played for Team Eastman in the 2010 Power Smart Manitoba Winter Games. He was selected by Everett in the seventh round (150th overall) of the WHL Bantam Draft.
2010-11: Lotz played for the Eastman Selects in the Manitoba midget minor AAA league. He appeared in 21 games and was 4-13 with a 3.76 goals against.
2011-12: Lotz appeared in 17 games for the Everett Silvertips as a backup to Chicago Blackhawks prospect Kent Simpson in his first WHL season. He was 2-9-2 with a 4.19 goals against and .886 save percentage. The Silvertips reached the WHL playoffs, finishing fourth in the U.S. Division despite the league's fourth-worst record. Lotz made one appearance in the four-game series with Tri-City, stopping 17 of 19 shots in 32 minutes of action. He represented Canada Western in the 2012 U17 World Hockey Challenge and in three games posted a 5.36 goals against and .866 save percentage.
2012-13: Lotz and former Seattle Thunderbirds goalie Daniel Cotton split the goaltending chores for Everett in his second WHL season. In 42 games he was 15-19-4 with 1 shutout and had a 3.37 goals against and .907 save percentage. The Silvertips again reached the WHL playoffs, despite finishing last in the U.S. Division. Lotz played in all six games in the first round series with Portland and was 2-4 with a 5.06 goals against and .888 save percentage. Lotz was selected to Canada's U18 team for the 2013 World Junior Championship but did not see any action as the team's third goalie in Sochi. Canada defeated the USA, 3-2 in the gold medal game. He was ranked 10th amongst North American goalies in Central Scouting's final rankings prior to the 2013 NHL Draft.