[1][2] The battalion's anniversary falls, as for all engineer units, on 24 June 1918, the last day of the Second Battle of the Piave River.

In March 1941, the "Trento" division was shipped to Libya for the Western Desert campaign.

On 13 May 1943, the battalion surrendered to the allies and was declared lost due to wartime events.

[1][2] On 13 November 1943, the Italian Co-belligerent Army reformed the LI Mixed Engineer Battalion in Colli a Volturno.

Initially the battalion served with the I Motorized Grouping, which fought on the allied side in the Italian campaign.

On 22 March 1944, the battalion joined the newly formed Italian Liberation Corps.

On 30 September 1944, the battalion was assigned to the newly formed Combat Group "Legnano".

For its service during the Italian campaign the battalion was awarded a Silver Medal of Military Valor.

[1][2] After the end of the war the battalion was based in Bergamo and remained assigned to the Combat Group "Legnano".

As the 51st Engineer Battalion "Simeto" supported the division-level Sicily Military Region, the battalion was named for the Simeto river in Sicily, along which Royal Italian Army units fought British Army paratroopers for control of the Primosole bridge during Operation Fustian.

On 5 March 1983, the President of the Italian Republic Sandro Pertini granted with decree 218 the battalion a flag.