He made his first appearance for Italy in 1999, and since then has earned 40 caps for the national team. He made his Test debut against Scotland on 6 March, although earlier that year he played for Italy against a non-cap French XV, and in 1997 he represented Italy 'A' against Denmark. He became a regular in the Italian Test side, and in 2003 was included in their World Cup squad for Australia. He played in three matches at the World Cup, against Tonga, Canada and Wales.
Dallan is an accomplished singer and led the singing of the Italian National Anthem for the international against the All Blacks held at the San Siro Stadium in November 2009.