In November 2001, Santos obtained Japanese citizenship. He made his first appearance for Japan national team on March 21, 2002 against Ukraine, and he was part of Philippe Troussier's selection for the 2002 World Cup. He was the second foreign-born person to play for Japan in the World Cup after Wagner Lopes, who played in the 1998 World Cup and also the fifth naturalized citizen to play for Japan after Daishiro Yoshimura, George Yonashiro, Ruy Ramos, and Lopes.