In the medal round, he won his first match against Daeyong Kwon of South Korea, 15-11, 15-2, but lost to Colombian Mario Mercado in a tie-breaker, 15-13, 10-15, 11-9, in the Round of 16. Iwaasa was a finalist at the World Racquetball Tour 2018 Canadian Open in Calgary, where he lost to Andree Parrilla in the final, 15-11, 15-13. He reached the final by defeating Gerardo Franco in the semi-finals, 15-7, 15-11. In the 2018-19 season, Iwaasa was runner up to Samuel Murray at both the 1st National Team Selection Event in Valleyfield, Québec, where he was beaten in three games, 9-15, 15-6, 11-6, and the 2nd National Team Selection Event in Grande Prairie, Alberta, losing 15-10, 15-10. In the second Racquetball Canada National Team Selection event of 2018-19 in Grande Prairie, Alberta, Iwaasa was 2nd to Murray, who won their final, 15-10, 15-10, in the final. He beat Trevor Webb in the semi-finals, 15-4, 14-15, 11-9. Iwaasa was a member of Team Canada for the 2019 Pan American Racquetball Championships in Barranquilla, Colombia, where he reached an international final for the first time. Iwaasa and Samuel Murray were finalists in Men's Doubles. They beat Costa Ricans Andres Acuña and Felipe Camacho in the semi-finals, 8-15, 15-1, 11-3, but lost to Bolivians Roland Keller and Conrrado Moscoso, 2-15, 15-9, 11-2, in the final. Iwaasa also played Men's Singles in Barranquilla, where he lost in the Round of 16 to eventual Pan Am Champion Carlos Keller of Bolivia, 15-10, 15-9. Iwaasa was runner up in Men's Singles at the 2019 Canadian Championships, as he lost in the final to Samuel Murray, 15-3, 15-6, in Langley, British Columbia. He beat Tim Landeryou in the semi-finals, 15-13, 15-2. Iwaasa played doubles with Trevor Webb for the first time, and they finished 3rd. They lost in the semi-finals to Murray and his brother Tommy, 11-15, 15-10, 11-4.