Kigab competed for Canada at the 2015 FIBA U19 World Cup and the 2016 FIBA Americas U18 Championship. In July 2017, he was a key player on a Canada team that captured gold at the FIBA U19 World Cup, averaging 14.7 points and 10.6 rebounds, as well as 2.3 assists per game. For his efforts, he was named to the tournament's All-Star Five.