The following year, Schafer suited up for Japan at the 2017 FIBA Under-19 Basketball World Cup, where he averaged 5.0 points, 4.9 rebounds and 0.1 assists per game and was the team's second-leading rebounder. Schafer posted a double-double twice, 11 points and 10 rebounds against Mali and 10 points and 10 rebounds versus Korea.