In March 2004, Tamada was selected the Japan national team for 2006 World Cup qualification. At this qualification, he debuted against Singapore on March 31. He became a regular player soon. In July, he was selected the Japan for 2004 Asian Cup and played all 6 matches. He scored 2 goals in the semifinal and 1 goal in the final, and Japan won the champions. In 2006, he also played at 2006 World Cup. He played 2 matches and scored 1 goal against Brazil. After the 2006 World Cup, he was not selected the Japan under new manager Ivica Osim. In 2008, Tamada was selected the Japan again under new manager Takeshi Okada. He played many matches again and he played at 2010 World Cup. He played 72 games and scored 16 goals for Japan until 2010.