A Silver color metal and enamel device 1 1/8 inches (2.86 cm) in diameter consisting of a white framed trestle bent within a scarlet annulet, bearing the motto "HONOR COURAGE GLORY" in Silver letters.
Scarlet and white are the colors of the Corps of Engineers. The trestle from the coat of rams of the Battalion is emblematic of the technical duties of the unit. The annulet, a continuous circle, inscribed with the motto "Honor - Courage ? Glory" reflect the spirit and character of the Battalion's personnel.
The distinctive unit insignia was originally approved for the 18th Engineer Regiment (Combat) on 1 October 1941. It was redesignated for the 18th Engineer Combat Battalion on 26 May 1945. The insignia was redesignated for the 18th Engineer Battalion on 17 November 1967.