Filion debuted with the Dominican national team at youth level, and was one of the best players of his team during the 2001 FIBA Under-21 World Championship in Saitama, Japan: he averaged 15.1 points, 3 rebounds and 1.4 assists per game. The Dominican Republic Under-21 team ended the tournament in 4th place. He then made his debut with the senior national team in 2003 and played during the 2003 Centrobasket, averaging 7 points and 3.7 rebounds per game, winning the silver medal. Filion was then called up with the national team for the 2003 Pan American Games in early August; during the competition he averaged 12.1 points, 4 rebounds and 1.9 assists per game, and the Dominican Republic won the silver medal. Later that month, Filion participated with his team in the 2003 Tournament of the Americas, where he had an 18-point, 6-rebound performance against the United States, and a 15-point performance against Puerto Rico.
