Tuqiri's talent attracted the interest of the Australian Rugby Union, and at the end of the 2002 football season he announced that he had signed a contract to play rugby union in 2003 with the New South Wales Waratahs, and was therefore leaving rugby league. In 2003, he switched codes, moving from rugby league to play rugby with the Waratahs. Tuqiri's transition to rugby union proved to be successful, and his speed and strength gained him selection for the Wallabies, for whom he made his international union debut in June 2003 against Ireland, becoming Australia's 43rd dual code rugby international.