A Silver color metal and enamel device 1 1/8 inches (2.86 cm) in width overall consisting of a shield blazoned as follows:  Azure (Teal Blue) a saltire Argent charged with two pyrotechnic projectors of the first, overall a mullet of four points Tenné fimbriated of the second.  Attached below the shield a Silver arched scroll inscribed “AD ARCANA TUTANDA” (To Keep Official Secrets Safe) in Teal Blue letters.

Teal blue and white were the colors associated with the former Army Security Agency Battalion as a branch immaterial unit.  The pyrotechnic projectors allude to the historical signal and reconnaissance missions of the unit, crossed to symbolize protection and security corresponding to the unit motto, “Ad Arcana Tutanda” (To Keep Official Secrets Safe).  The four pointed star refers to the four battle honors awarded for service in World War II and also symbolizes intelligence, reconnaissance, communications and signal, vital functions of the battalion.  The color orange further alludes to its historical signal function.  

The distinctive unit insignia was originally approved for the 305th Army Security Agency Battalion on 27 September 1957.  It was redesignated for the 305th Military Intelligence Battalion on 18 June 1990. The symbolism was updated on 24 February 2023.

Shield.  Azure (Teal Blue) a saltire Argent charged with pyrotechnic projectors of the first, overall a mullet of four points Tenné fimbriated of the second.

Crest.  On a wreath of the colors Argent and Azure (Teal Blue) issuant from the battlements of a tower Proper a fleur-de-lis Or between two griffin heads respectant Gules beaked Or.

Motto.  AD ARCANA TUTANDA (To Keep Official Secrets Safe).

Shield.  Teal blue and white were the colors associated with the former Army Security Agency Battalion as a branch immaterial unit.  The pyrotechnic projectors allude to the historical signal and reconnaissance missions of the unit, crossed to symbolize protection and security corresponding to the unit motto, “Ad Arcana Tutanda” (To Keep Official Secrets Safe).  The four pointed star refers to the four battle honors awarded for service in World War II and also symbolizes intelligence, reconnaissance, communications and signal, vital functions of the battalion.  The color orange further alludes to its historical signal function. 

Crest.  The tower symbolizes a strong defense and military preparedness.  The griffins, personifying vigilance, stand prepared to meet all threats.  Red denotes courage and zeal.  The tower and fleur-de-lis commemorate the unit’s World War II service in Northern Europe.

The coat of arms was originally approved for the 305th Army Security Agency Battalion on 27 September 1957.  It was redesignated for the 305th Military Intelligence Battalion and amended to add a crest on 5 October 1990. The symbolism was updated on 24 February 2023.