The 21^st Engineer Regiment was constituted in Trani (Bari) on 1^st October 1937. Destined to Libya, the unit arrived to Bengasi on 17^th October. Because of war events the Regiment was dissolved in November 1942.

On 1^st January 1953 the 21^st Pioneers Engineer Battalion was formed in Trani. On 19^th January 1963 the unit was moved to Vicenza. With the reorganization of the Army, on 1^st October 1975 it became 21^st "Timavo" Pioneers Engineer Battalion inheriting the traditions and the Flag of the 21^st Engineer Regiment. The Battalion was dissolved on 31^st December 1979; only a company remained for the needs of the 3^rd "Aquileia" Brigade.

On 1^st January 1980 it was renamed 21^st "Timavo" Engineer Battalion that, with the reorganization of the Army, it was dissolved on 20^th September 1993 before being reconstituted in Caserta as 21^st Pioneers Engineer Battalion.

After having changed its structure, since 1^st October 2000 it was named 21^st Sappers Engineer Regiment and on 1^st December it passed at the dependencies of the "Garibaldi" Bersaglieri Brigade.

It participated in the following operations: "Alba" in Albania, in 2000; "Joint Guardian" in Kosovo, in 1999, 2000, 2001 and 2005; "Domino" on the national territory, in 2002; "ISAF" in Afghanistan, in 2003 and 2012; "Enduring Freedom" in Afghanistan, in 2003; "Ancient Babylon" in Iraq, in 2003, 2005 and 2006; "Leonte" in Lebanon, in 2008 and 2010; "Clean Streets" on the national territory, from 2008 to 2012; "Safe Streets" on the national territory, from 2009 to 2013.