Diamanti made his debut with the Italy national team on 17 November 2010, for manager Cesare Prandelli, in a friendly match against Romania.
He played only the first half of his debut game before being substituted.
In May 2012, he was named in the provisional, 32-man Italian squad for UEFA Euro 2012 and came on as a substitute in the final group match against the Republic of Ireland on 18 June 2012, setting up Mario Balotelli's goal from a corner as Italy won the match 2–0 to advance to the quarter-finals.
In the quarter-final against England on 24 June 2012, Diamanti came on in the second half for Antonio Cassano and scored the winning penalty to give Italy a 4–2 penalty shoot-out win.

Diamanti was selected for Italy's squad at the 2013 FIFA Confederations Cup in Brazil.
He scored one goal at the tournament, from a free kick in the bronze medal game against Uruguay, his first international goal; he was also involved in Davide Astori's opening goal, as the latter scored off the rebound after Diamanti's free kick had hit the crossbar.
Italy went on to win the match 3–2 on penalties following a 2–2 deadlock after extra time.
Diamanti made his debut with the Italy national team on 17 November 2010, for manager Cesare Prandelli, in a friendly match against Romania. He played only the first half of his debut game before being substituted. In May 2012, he was named in the provisional, 32-man Italian squad for UEFA Euro 2012 and came on as a substitute in the final group match against the Republic of Ireland on 18 June 2012, setting up Mario Balotelli's goal from a corner as Italy won the match 2–0 to advance to the quarter-finals. In the quarter-final against England on 24 June 2012, Diamanti came on in the second half for Antonio Cassano and scored the winning penalty to give Italy a 4–2 penalty shoot-out win.
Diamanti was selected for Italy's squad at the 2013 FIFA Confederations Cup in Brazil. He scored one goal at the tournament, from a free kick in the bronze medal game against Uruguay, his first international goal; he was also involved in Davide Astori's opening goal, as the latter scored off the rebound after Diamanti's free kick had hit the crossbar. Italy went on to win the match 3–2 on penalties following a 2–2 deadlock after extra time.
Alessandro Diamanti